doc-src/isac/jrocnik/eJMT-paper/jrocnik_eJMT.tex
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   664 reasonably short and easily comprehensible, still requires lots of
   664 reasonably short and easily comprehensible, still requires lots of
   665 work (and is definitely out of scope of our case study).
   665 work (and is definitely out of scope of our case study).
   666 
   666 
   667 \paragraph{At the state-of-the-art in mechanization of knowledge} in
   667 \paragraph{At the state-of-the-art in mechanization of knowledge} in
   668 engineering sciences, the process does not stop with the mechanization of
   668 engineering sciences, the process does not stop with the mechanization of
   669 mathematics traditionally used in these sciences. Rather, ``Formal Methods''~\cite{TODO-formal-methods}
   669 mathematics traditionally used in these sciences. Rather, ``Formal Methods''~\cite{
       
   670 fm-03}
   670 are expected to proceed to formal and explicit description of physical items.  Signal Processing,
   671 are expected to proceed to formal and explicit description of physical items.  Signal Processing,
   671 for instance is concerned with physical devices for signal acquisition
   672 for instance is concerned with physical devices for signal acquisition
   672 and reconstruction, which involve measuring a physical signal, storing
   673 and reconstruction, which involve measuring a physical signal, storing
   673 it, and possibly later rebuilding the original signal or an
   674 it, and possibly later rebuilding the original signal or an
   674 approximation thereof. For digital systems, this typically includes
   675 approximation thereof. For digital systems, this typically includes
   675 sampling and quantization; devices for signal compression, including
   676 sampling and quantization; devices for signal compression, including
   676 audio compression, image compression, and video compression, etc.
   677 audio compression, image compression, and video compression, etc.
   677 ``Domain engineering''\cite{db-domain-engineering} is concerned with
   678 ``Domain engineering''\cite{db:dom-eng} is concerned with
   678 {\em specification} of these devices' components and features; this
   679 {\em specification} of these devices' components and features; this
   679 part in the process of mechanization is only at the beginning in domains
   680 part in the process of mechanization is only at the beginning in domains
   680 like Signal Processing.
   681 like Signal Processing.
   681 
   682 
   682 \subparagraph{TP-based programming, concern of this paper,} is determined to
   683 \subparagraph{TP-based programming, concern of this paper,} is determined to
   683 add ``algorithmic knowledge'' in Fig.\ref{fig:mathuni} on
   684 add ``algorithmic knowledge'' in Fig.\ref{fig:mathuni} on
   684 p.\pageref{fig:mathuni}.  As we shall see below, TP-based programming
   685 p.\pageref{fig:mathuni}.  As we shall see below, TP-based programming
   685 starts with a formal {\em specification} of the problem to be solved.
   686 starts with a formal {\em specification} of the problem to be solved.
       
   687 \begin{figure}
       
   688   \begin{center}
       
   689     \includegraphics{fig/universe}
       
   690     \caption{Didactic ``Math-Universe'': Algorithmic Knowledge
       
   691 (Programs) is combined with Application-oriented Knowledge
       
   692 (Specifications) and Deductive Knowledge (Axioms, Definitions,
       
   693 Theorems). The Result leads to a three dimensional math
       
   694 universe.}
       
   695     \label{fig:mathuni}
       
   696   \end{center}
       
   697 \end{figure}
   686 
   698 
   687 
   699 
   688 \subsection{Specification of the Problem}\label{spec}
   700 \subsection{Specification of the Problem}\label{spec}
   689 %WN <--> \chapter 7 der Thesis
   701 %WN <--> \chapter 7 der Thesis
   690 %WN die Argumentation unten sollte sich NUR auf Verifikation beziehen..
   702 %WN die Argumentation unten sollte sich NUR auf Verifikation beziehen..
   931           ``b'' the denominator) and returns.
   943           ``b'' the denominator) and returns.
   932 \item[05] handels the error case and reports that the function is not able to
   944 \item[05] handels the error case and reports that the function is not able to
   933           solve the given problem.
   945           solve the given problem.
   934 \end{description}
   946 \end{description}
   935 
   947 
   936 \subsection{Implementation of the TP-based Program}\label{progr}
   948 \subsection{Implementation of the TP-based Program}\label{progr} 
   937 
   949 So finally all the prerequisites are described and the program can be
   938 \paragraph{After introducing} neccesarry informations about the {\sisac{}}
   950 presented which computes a solution for the problem of the running
   939 System, the main part of a implementation in the TP-bases language can be shown.
   951 example from p.\pageref{fig-interactive}. The reader remembering the
   940 \par
   952 introduction of the programming language in \S\ref{PL-isab} might
   941 Solution~\ref{s:impl} shows us the implementation of the
   953 immediately comprehend the program:
   942 Inverse-Z-Transformation, a description on the code is given afterwards.
   954 {\small\it
   943 
   955 \begin{tabbing}\label{s:impl}
   944 \begin{solution}
   956 123l\=123\=123\=123\=123\=123\=123\=((x\=123\=(x \=123\=123\=\kill
   945 \label{s:impl}
       
   946 \begin{tabbing}
       
   947 \small\it
       
   948 123l\=123\=123\=123\=123\=123\=123\=123\=123\=(x \=123\=123\=\kill
       
   949 \> \\
   957 \> \\
   950 \> \\
   958 \> \\
   951 \>{\rm 01}\>  {\tt Program} InverseZTransform (X\_eq::bool) =   \\
   959 \>{\rm 01}\>  {\tt Program} InverseZTransform (X\_eq::bool) =   \\
   952 \>{\rm 02}\>\>  {\tt LET}                                       \\
   960 \>{\rm 02}\>\>  {\tt LET}                                       \\
   953 \>{\rm 03}\>\>\>  X\_eq = {\tt Take} X\_eq ;   \\
   961 \>{\rm 03}\>\>\>  X\_eq = {\tt Take} X\_eq ;   \\
   954 \>{\rm 04}\>\>\>  X\_eq = {\tt Rewrite} ruleZY X\_eq ; \\
   962 \>{\rm 04}\>\>\>  X\_eq = {\tt Rewrite} ruleZY X\_eq ; \\
   955 \>{\rm 05}\>\>\>  (X\_z::real) = lhs X\_eq ;       \\ %no inside-out evaluation
   963 \>{\rm 05}\>\>\>  (X\_z::real) = lhs X\_eq ;       \\ %no inside-out evaluation
   956 \>{\rm 06}\>\>\>  (z::real) = argument\_in X\_z; \\
   964 \>{\rm 06}\>\>\>  (z::real) = argument\_in X\_z; \\
   957 \>{\rm 07}\>\>\>  (part\_frac::real) = {\tt SubProblem} \\
   965 \>{\rm 07}\>\>\>  (part\_frac::real) = {\tt SubProblem} \\
   958 \>{\rm 08}\>\>\>\>\>\>\>\>  ( \> Isac, \\
   966 \>{\rm 08}\>\>\>\>\>\>\>\>  ( Isac, [partial\_fraction, rational, simplification], [] )\\
   959 \>{\rm 08}\>\>\>\>\>\>\>\>\>  [partial\_fraction, rational, simplification]\\
   967 %\>{\rm 10}\>\>\>\>\>\>\>\>\>  [simplification, of\_rationals, to\_partial\_fraction] ) \\
   960 \>{\rm 09}\>\>\>\>\>\>\>\>\>  [simplification,of\_rationals,to\_partial\_fraction] ) \\
   968 \>{\rm 09}\>\>\>\>\>\>\>\>  [ (rhs X\_eq)::real, z::real ]; \\
   961 \>{\rm 10}\>\>\>\>\>\>\>\>  [ (rhs X\_eq)::real, z::real ]; \\
   969 \>{\rm 10}\>\>\>  (X'\_eq::bool) = {\tt Take} ((X'::real =$>$ bool) z = ZZ\_1 part\_frac) ; \\
   962 \>{\rm 12}\>\>\>  (X'\_eq::bool) = {\tt Take} ((X'::real =$>$ bool) z = ZZ\_1 part\_frac) ; \\
   970 
   963 
   971 \>{\rm 11}\>\>\>  X'\_eq = (({\tt Rewrite\_Set} ruleYZ) @@   \\
   964 \>{\rm 12}\>\>\>  X'\_eq = {\tt Rewrite\_Set} ruleYZ X'\_eq ;   \\
   972 \>{\rm 12}\>\>\>\>\>  $\;\;$ ({\tt Rewrite\_Set} inverse\_z)) X'\_eq \\
   965 \>{\rm 15}\>\>\>  X'\_eq = {\tt Rewrite\_Set} inverse\_z X'\_eq \\
   973 \>{\rm 13}\>\>  {\tt IN } \\
   966 \>{\rm 16}\>\>  {\tt IN } \\
   974 \>{\rm 14}\>\>\>  X'\_eq\\
   967 \>{\rm 15}\>\>\>  X'\_eq
   975 \end{tabbing}}
   968 \end{tabbing}
       
   969 \end{solution}
       
   970 
       
   971 % ORIGINAL FROM Inverse_Z_Transform.thy
   976 % ORIGINAL FROM Inverse_Z_Transform.thy
   972 % "Script InverseZTransform (X_eq::bool) =            "^(*([], Frm), Problem (Isac, [Inverse, Z_Transform, SignalProcessing])*)
   977 % "Script InverseZTransform (X_eq::bool) =            "^(*([], Frm), Problem (Isac, [Inverse, Z_Transform, SignalProcessing])*)
   973 % "(let X = Take X_eq;                                "^(*([1], Frm), X z = 3 / (z - 1 / 4 + -1 / 8 * (1 / z))*)
   978 % "(let X = Take X_eq;                                "^(*([1], Frm), X z = 3 / (z - 1 / 4 + -1 / 8 * (1 / z))*)
   974 % "  X' = Rewrite ruleZY False X;                     "^(*([1], Res), ?X' z = 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z)))*)
   979 % "  X' = Rewrite ruleZY False X;                     "^(*([1], Res), ?X' z = 3 / (z * (z - 1 / 4 + -1 / 8 * (1 / z)))*)
   975 % "  (X'_z::real) = lhs X';                           "^(*            ?X' z*)
   980 % "  (X'_z::real) = lhs X';                           "^(*            ?X' z*)
   986 % "  pbz_eq = drop_questionmarks pbz_eq;              "^(*               4 * (z / (z - 1 / 2)) + -4 * (z / (z - -1 / 4))*)
   991 % "  pbz_eq = drop_questionmarks pbz_eq;              "^(*               4 * (z / (z - 1 / 2)) + -4 * (z / (z - -1 / 4))*)
   987 % "  (X_zeq::bool) = Take (X_z = rhs pbz_eq);         "^(*([4], Frm), X_z = 4 * (z / (z - 1 / 2)) + -4 * (z / (z - -1 / 4))*)
   992 % "  (X_zeq::bool) = Take (X_z = rhs pbz_eq);         "^(*([4], Frm), X_z = 4 * (z / (z - 1 / 2)) + -4 * (z / (z - -1 / 4))*)
   988 % "  n_eq = (Rewrite_Set inverse_z False) X_zeq;      "^(*([4], Res), X_z = 4 * (1 / 2) ^^^ ?n * ?u [?n] + -4 * (-1 / 4) ^^^ ?n * ?u [?n]*)
   993 % "  n_eq = (Rewrite_Set inverse_z False) X_zeq;      "^(*([4], Res), X_z = 4 * (1 / 2) ^^^ ?n * ?u [?n] + -4 * (-1 / 4) ^^^ ?n * ?u [?n]*)
   989 % "  n_eq = drop_questionmarks n_eq                   "^(*            X_z = 4 * (1 / 2) ^^^ n * u [n] + -4 * (-1 / 4) ^^^ n * u [n]*)
   994 % "  n_eq = drop_questionmarks n_eq                   "^(*            X_z = 4 * (1 / 2) ^^^ n * u [n] + -4 * (-1 / 4) ^^^ n * u [n]*)
   990 % "in n_eq)"                                            (*([], Res), X_z = 4 * (1 / 2) ^^^ n * u [n] + -4 * (-1 / 4) ^^^ n * u [n]*)
   995 % "in n_eq)"                                            (*([], Res), X_z = 4 * (1 / 2) ^^^ n * u [n] + -4 * (-1 / 4) ^^^ n * u [n]*)
       
   996 As mentioned in \S\ref{PL} the program is purely functional and lacks
       
   997 any input statements and output statements. So the steps of
       
   998 calculation towards a solution (and interactive tutoring in step-wise
       
   999 problem solving) are created as a side-effect by Lucas-Interpretation.
       
  1000 The break-points for the interpreter are the tactics \textit{Take},
       
  1001 \textit{Rewrite}, \textit{SubProblem} and \textit{Rewrite\_Set} in the
       
  1002 above lines {\rm 03, 04, 07, 10, 11} and {\rm 12} respectively. These
       
  1003 tactics produce the lines in the calculation on p.\pageref{flow-impl}.
       
  1004 
       
  1005 The above program also indicates the dominant role of interactive
       
  1006 selection of knowledge in the three-dimensional universe of
       
  1007 mathematics as depicted in Fig.\ref{fig:mathuni} on
       
  1008 p.\pageref{fig:mathuni}, The \textit{SubProblem} in the above lines
       
  1009 {\rm 07..09} is more than a function call with the actual arguments
       
  1010 \textit{[ (rhs X\_eq)::real, z::real ]}. The programmer has to determine
       
  1011 three items:
       
  1012 \begin{enumerate}
       
  1013 \item the theory, in the example \textit{Isac} because different
       
  1014 methods can be selected in Pt.3 below, which are defined in different
       
  1015 theories with \textit{Isac} collecting them.
       
  1016 \item the specification identified by \textit{[partial\_fraction, rational, simplification]} in the tree of specifications; this specification is analogous to the specification of the main program described in \S\ref{spec}.
       
  1017 \item the method in the above example is \textit{[ ]}, i.e. empty, which allows
       
  1018 the interpreter to select one of the methods predefined in the specification
       
  1019 \end{enumerate}
       
  1020 
       
  1021 .\\.\\.\\
       
  1022 
   991 
  1023 
   992 \section{Workflow of Programming in the Prototype}\label{workflow}
  1024 \section{Workflow of Programming in the Prototype}\label{workflow}
   993 
  1025 
   994 \subsection{Preparations and Trials}\label{flow-prep}
  1026 \subsection{Preparations and Trials}\label{flow-prep}
   995 TODO Build\_Inverse\_Z\_Transform.thy ... ``imports PolyEq DiffApp Partial\_Fractions''
  1027 TODO Build\_Inverse\_Z\_Transform.thy ... ``imports PolyEq DiffApp Partial\_Fractions''
  1063 TODO http://www.ist.tugraz.at/isac/index.php/Extend\_ISAC\_Knowledge\#Add\_an\_example ?
  1095 TODO http://www.ist.tugraz.at/isac/index.php/Extend\_ISAC\_Knowledge\#Add\_an\_example ?
  1064 
  1096 
  1065 
  1097 
  1066 
  1098 
  1067 
  1099 
  1068 \newpage
  1100 % \newpage
  1069 -------------------------------------------------------------------
  1101 % -------------------------------------------------------------------
  1070 
  1102 % 
  1071 Material, falls noch Platz bleibt ...
  1103 % Material, falls noch Platz bleibt ...
  1072 
  1104 % 
  1073 -------------------------------------------------------------------
  1105 % -------------------------------------------------------------------
  1074 
  1106 % 
  1075 
  1107 % 
  1076 \subsubsection{Trials on Notation and Termination}
  1108 % \subsubsection{Trials on Notation and Termination}
  1077 
  1109 % 
  1078 \paragraph{Technical notations} are a big problem for our piece of software,
  1110 % \paragraph{Technical notations} are a big problem for our piece of software,
  1079 but the reason for that isn't a fault of the software itself, one of the
  1111 % but the reason for that isn't a fault of the software itself, one of the
  1080 troubles comes out of the fact that different technical subtopics use different
  1112 % troubles comes out of the fact that different technical subtopics use different
  1081 symbols and notations for a different purpose. The most famous example for such
  1113 % symbols and notations for a different purpose. The most famous example for such
  1082 a symbol is the complex number $i$ (in cassique math) or $j$ (in technical
  1114 % a symbol is the complex number $i$ (in cassique math) or $j$ (in technical
  1083 math). In the specific part of signal processing one of this notation issues is
  1115 % math). In the specific part of signal processing one of this notation issues is
  1084 the use of brackets --- we use round brackets for analoge signals and squared
  1116 % the use of brackets --- we use round brackets for analoge signals and squared
  1085 brackets for digital samples. Also if there is no problem for us to handle this
  1117 % brackets for digital samples. Also if there is no problem for us to handle this
  1086 fact, we have to tell the machine what notation leads to wich meaning and that
  1118 % fact, we have to tell the machine what notation leads to wich meaning and that
  1087 this purpose seperation is only valid for this special topic - signal
  1119 % this purpose seperation is only valid for this special topic - signal
  1088 processing.
  1120 % processing.
  1089 \subparagraph{In the programming language} itself it is not possible to declare
  1121 % \subparagraph{In the programming language} itself it is not possible to declare
  1090 fractions, exponents, absolutes and other operators or remarks in a way to make
  1122 % fractions, exponents, absolutes and other operators or remarks in a way to make
  1091 them pretty to read; our only posssiblilty were ASCII characters and a handfull
  1123 % them pretty to read; our only posssiblilty were ASCII characters and a handfull
  1092 greek symbols like: $\alpha, \beta, \gamma, \phi,\ldots$.
  1124 % greek symbols like: $\alpha, \beta, \gamma, \phi,\ldots$.
  1093 \par
  1125 % \par
  1094 With the upper collected knowledge it is possible to check if we were able to
  1126 % With the upper collected knowledge it is possible to check if we were able to
  1095 donate all required terms and expressions.
  1127 % donate all required terms and expressions.
  1096 
  1128 % 
  1097 \subsubsection{Definition and Usage of Rules}
  1129 % \subsubsection{Definition and Usage of Rules}
  1098 
  1130 % 
  1099 \paragraph{The core} of our implemented problem is the Z-Transformation, due
  1131 % \paragraph{The core} of our implemented problem is the Z-Transformation, due
  1100 the fact that the transformation itself would require higher math which isn't
  1132 % the fact that the transformation itself would require higher math which isn't
  1101 yet avaible in our system we decided to choose the way like it is applied in
  1133 % yet avaible in our system we decided to choose the way like it is applied in
  1102 labratory and problem classes at our university - by applying transformation
  1134 % labratory and problem classes at our university - by applying transformation
  1103 rules (collected in transformation tables).
  1135 % rules (collected in transformation tables).
  1104 \paragraph{Rules,} in {\sisac{}}'s programming language can be designed by the
  1136 % \paragraph{Rules,} in {\sisac{}}'s programming language can be designed by the
  1105 use of axiomatizations like shown in Example~\ref{eg:ruledef}
  1137 % use of axiomatizations like shown in Example~\ref{eg:ruledef}
  1106 
  1138 % 
  1107 \begin{example}
  1139 % \begin{example}
  1108   \label{eg:ruledef}
  1140 %   \label{eg:ruledef}
  1109   \hfill\\
  1141 %   \hfill\\
  1110   \begin{verbatim}
  1142 %   \begin{verbatim}
  1111   axiomatization where
  1143 %   axiomatization where
  1112     rule1: ``1 = $\delta$[n]'' and
  1144 %     rule1: ``1 = $\delta$[n]'' and
  1113     rule2: ``|| z || > 1 ==> z / (z - 1) = u [n]'' and
  1145 %     rule2: ``|| z || > 1 ==> z / (z - 1) = u [n]'' and
  1114     rule3: ``|| z || < 1 ==> z / (z - 1) = -u [-n - 1]''
  1146 %     rule3: ``|| z || < 1 ==> z / (z - 1) = -u [-n - 1]''
  1115   \end{verbatim}
  1147 %   \end{verbatim}
  1116 \end{example}
  1148 % \end{example}
  1117 
  1149 % 
  1118 This rules can be collected in a ruleset and applied to a given expression as
  1150 % This rules can be collected in a ruleset and applied to a given expression as
  1119 follows in Example~\ref{eg:ruleapp}.
  1151 % follows in Example~\ref{eg:ruleapp}.
  1120 
  1152 % 
  1121 \begin{example}
  1153 % \begin{example}
  1122   \hfill\\
  1154 %   \hfill\\
  1123   \label{eg:ruleapp}
  1155 %   \label{eg:ruleapp}
  1124   \begin{enumerate}
  1156 %   \begin{enumerate}
  1125   \item Store rules in ruleset:
  1157 %   \item Store rules in ruleset:
  1126   \begin{verbatim}
  1158 %   \begin{verbatim}
  1127   val inverse_Z = append_rls "inverse_Z" e_rls
  1159 %   val inverse_Z = append_rls "inverse_Z" e_rls
  1128     [ Thm ("rule1",num_str @{thm rule1}),
  1160 %     [ Thm ("rule1",num_str @{thm rule1}),
  1129       Thm ("rule2",num_str @{thm rule2}),
  1161 %       Thm ("rule2",num_str @{thm rule2}),
  1130       Thm ("rule3",num_str @{thm rule3})
  1162 %       Thm ("rule3",num_str @{thm rule3})
  1131     ];\end{verbatim}
  1163 %     ];\end{verbatim}
  1132   \item Define exression:
  1164 %   \item Define exression:
  1133   \begin{verbatim}
  1165 %   \begin{verbatim}
  1134   val sample_term = str2term "z/(z-1)+z/(z-</delta>)+1";\end{verbatim}
  1166 %   val sample_term = str2term "z/(z-1)+z/(z-</delta>)+1";\end{verbatim}
  1135   \item Apply ruleset:
  1167 %   \item Apply ruleset:
  1136   \begin{verbatim}
  1168 %   \begin{verbatim}
  1137   val SOME (sample_term', asm) = 
  1169 %   val SOME (sample_term', asm) = 
  1138     rewrite_set_ thy true inverse_Z sample_term;\end{verbatim}
  1170 %     rewrite_set_ thy true inverse_Z sample_term;\end{verbatim}
  1139   \end{enumerate}
  1171 %   \end{enumerate}
  1140 \end{example}
  1172 % \end{example}
  1141 
  1173 % 
  1142 The use of rulesets makes it much easier to develop our designated applications,
  1174 % The use of rulesets makes it much easier to develop our designated applications,
  1143 but the programmer has to be careful and patient. When applying rulesets
  1175 % but the programmer has to be careful and patient. When applying rulesets
  1144 two important issues have to be mentionend:
  1176 % two important issues have to be mentionend:
  1145 \subparagraph{How often} the rules have to be applied? In case of
  1177 % \subparagraph{How often} the rules have to be applied? In case of
  1146 transformations it is quite clear that we use them once but other fields
  1178 % transformations it is quite clear that we use them once but other fields
  1147 reuqire to apply rules until a special condition is reached (e.g.
  1179 % reuqire to apply rules until a special condition is reached (e.g.
  1148 a simplification is finished when there is nothing to be done left).
  1180 % a simplification is finished when there is nothing to be done left).
  1149 \subparagraph{The order} in which rules are applied often takes a big effect
  1181 % \subparagraph{The order} in which rules are applied often takes a big effect
  1150 and has to be evaluated for each purpose once again.
  1182 % and has to be evaluated for each purpose once again.
  1151 \par
  1183 % \par
  1152 In our special case of Signal Processing and the rules defined in
  1184 % In our special case of Signal Processing and the rules defined in
  1153 Example~\ref{eg:ruledef} we have to apply rule~1 first of all to transform all
  1185 % Example~\ref{eg:ruledef} we have to apply rule~1 first of all to transform all
  1154 constants. After this step has been done it no mather which rule fit's next.
  1186 % constants. After this step has been done it no mather which rule fit's next.
  1155 
  1187 % 
  1156 \subsubsection{Helping Functions}
  1188 % \subsubsection{Helping Functions}
  1157 
  1189 % 
  1158 \paragraph{New Programms require,} often new ways to get through. This new ways
  1190 % \paragraph{New Programms require,} often new ways to get through. This new ways
  1159 means that we handle functions that have not been in use yet, they can be 
  1191 % means that we handle functions that have not been in use yet, they can be 
  1160 something special and unique for a programm or something famous but unneeded in
  1192 % something special and unique for a programm or something famous but unneeded in
  1161 the system yet. In our dedicated example it was for example neccessary to split
  1193 % the system yet. In our dedicated example it was for example neccessary to split
  1162 a fraction into numerator and denominator; the creation of such function and
  1194 % a fraction into numerator and denominator; the creation of such function and
  1163 even others is described in upper Sections~\ref{simp} and \ref{funs}.
  1195 % even others is described in upper Sections~\ref{simp} and \ref{funs}.
  1164 
  1196 % 
  1165 \subsubsection{Trials on equation solving}
  1197 % \subsubsection{Trials on equation solving}
  1166 %simple eq and problem with double fractions/negative exponents
  1198 % %simple eq and problem with double fractions/negative exponents
  1167 \paragraph{The Inverse Z-Transformation} makes it neccessary to solve
  1199 % \paragraph{The Inverse Z-Transformation} makes it neccessary to solve
  1168 equations degree one and two. Solving equations in the first degree is no 
  1200 % equations degree one and two. Solving equations in the first degree is no 
  1169 problem, wether for a student nor for our machine; but even second degree
  1201 % problem, wether for a student nor for our machine; but even second degree
  1170 equations can lead to big troubles. The origin of this troubles leads from
  1202 % equations can lead to big troubles. The origin of this troubles leads from
  1171 the build up process of our equation solving functions; they have been
  1203 % the build up process of our equation solving functions; they have been
  1172 implemented some time ago and of course they are not as good as we want them to
  1204 % implemented some time ago and of course they are not as good as we want them to
  1173 be. Wether or not following we only want to show how cruel it is to build up new
  1205 % be. Wether or not following we only want to show how cruel it is to build up new
  1174 work on not well fundamentials.
  1206 % work on not well fundamentials.
  1175 \subparagraph{A simple equation solving,} can be set up as shown in the next
  1207 % \subparagraph{A simple equation solving,} can be set up as shown in the next
  1176 example:
  1208 % example:
  1177 
  1209 % 
  1178 \begin{example}
  1210 % \begin{example}
  1179 \begin{verbatim}
  1211 % \begin{verbatim}
  1180   
  1212 %   
  1181   val fmz =
  1213 %   val fmz =
  1182     ["equality (-1 + -2 * z + 8 * z ^^^ 2 = (0::real))",
  1214 %     ["equality (-1 + -2 * z + 8 * z ^^^ 2 = (0::real))",
  1183      "solveFor z",
  1215 %      "solveFor z",
  1184      "solutions L"];                                    
  1216 %      "solutions L"];                                    
  1185 
  1217 % 
  1186   val (dI',pI',mI') =
  1218 %   val (dI',pI',mI') =
  1187     ("Isac", 
  1219 %     ("Isac", 
  1188       ["abcFormula","degree_2","polynomial","univariate","equation"],
  1220 %       ["abcFormula","degree_2","polynomial","univariate","equation"],
  1189       ["no_met"]);\end{verbatim}
  1221 %       ["no_met"]);\end{verbatim}
  1190 \end{example}
  1222 % \end{example}
  1191 
  1223 % 
  1192 Here we want to solve the equation: $-1+-2\cdot z+8\cdot z^{2}=0$. (To give
  1224 % Here we want to solve the equation: $-1+-2\cdot z+8\cdot z^{2}=0$. (To give
  1193 a short overview on the commands; at first we set up the equation and tell the
  1225 % a short overview on the commands; at first we set up the equation and tell the
  1194 machine what's the bound variable and where to store the solution. Second step 
  1226 % machine what's the bound variable and where to store the solution. Second step 
  1195 is to define the equation type and determine if we want to use a special method
  1227 % is to define the equation type and determine if we want to use a special method
  1196 to solve this type.) Simple checks tell us that the we will get two results for
  1228 % to solve this type.) Simple checks tell us that the we will get two results for
  1197 this equation and this results will be real.
  1229 % this equation and this results will be real.
  1198 So far it is easy for us and for our machine to solve, but
  1230 % So far it is easy for us and for our machine to solve, but
  1199 mentioned that a unvariate equation second order can have three different types
  1231 % mentioned that a unvariate equation second order can have three different types
  1200 of solutions it is getting worth.
  1232 % of solutions it is getting worth.
  1201 \subparagraph{The solving of} all this types of solutions is not yet supported.
  1233 % \subparagraph{The solving of} all this types of solutions is not yet supported.
  1202 Luckily it was needed for us; but something which has been needed in this 
  1234 % Luckily it was needed for us; but something which has been needed in this 
  1203 context, would have been the solving of an euation looking like:
  1235 % context, would have been the solving of an euation looking like:
  1204 $-z^{-2}+-2\cdot z^{-1}+8=0$ which is basically the same equation as mentioned
  1236 % $-z^{-2}+-2\cdot z^{-1}+8=0$ which is basically the same equation as mentioned
  1205 before (remember that befor it was no problem to handle for the machine) but
  1237 % before (remember that befor it was no problem to handle for the machine) but
  1206 now, after a simple equivalent transformation, we are not able to solve
  1238 % now, after a simple equivalent transformation, we are not able to solve
  1207 it anymore.
  1239 % it anymore.
  1208 \subparagraph{Error messages} we get when we try to solve something like upside
  1240 % \subparagraph{Error messages} we get when we try to solve something like upside
  1209 were very confusing and also leads us to no special hint about a problem.
  1241 % were very confusing and also leads us to no special hint about a problem.
  1210 \par The fault behind is, that we have no well error handling on one side and
  1242 % \par The fault behind is, that we have no well error handling on one side and
  1211 no sufficient formed equation solving on the other side. This two facts are
  1243 % no sufficient formed equation solving on the other side. This two facts are
  1212 making the implemention of new material very difficult.
  1244 % making the implemention of new material very difficult.
  1213 
  1245 % 
  1214 \subsection{Formalization of missing knowledge in Isabelle}
  1246 % \subsection{Formalization of missing knowledge in Isabelle}
  1215 
  1247 % 
  1216 \paragraph{A problem} behind is the mechanization of mathematic
  1248 % \paragraph{A problem} behind is the mechanization of mathematic
  1217 theories in TP-bases languages. There is still a huge gap between
  1249 % theories in TP-bases languages. There is still a huge gap between
  1218 these algorithms and this what we want as a solution - in Example
  1250 % these algorithms and this what we want as a solution - in Example
  1219 Signal Processing. 
  1251 % Signal Processing. 
  1220 
  1252 % 
  1221 \vbox{
  1253 % \vbox{
  1222   \begin{example}
  1254 %   \begin{example}
  1223     \label{eg:gap}
  1255 %     \label{eg:gap}
  1224     \[
  1256 %     \[
  1225       X\cdot(a+b)+Y\cdot(c+d)=aX+bX+cY+dY
  1257 %       X\cdot(a+b)+Y\cdot(c+d)=aX+bX+cY+dY
  1226     \]
  1258 %     \]
  1227     {\small\textit{
  1259 %     {\small\textit{
  1228       \noindent A very simple example on this what we call gap is the
  1260 %       \noindent A very simple example on this what we call gap is the
  1229 simplification above. It is needles to say that it is correct and also
  1261 % simplification above. It is needles to say that it is correct and also
  1230 Isabelle for fills it correct - \emph{always}. But sometimes we don't
  1262 % Isabelle for fills it correct - \emph{always}. But sometimes we don't
  1231 want expand such terms, sometimes we want another structure of
  1263 % want expand such terms, sometimes we want another structure of
  1232 them. Think of a problem were we now would need only the coefficients
  1264 % them. Think of a problem were we now would need only the coefficients
  1233 of $X$ and $Y$. This is what we call the gap between mechanical
  1265 % of $X$ and $Y$. This is what we call the gap between mechanical
  1234 simplification and the solution.
  1266 % simplification and the solution.
  1235     }}
  1267 %     }}
  1236   \end{example}
  1268 %   \end{example}
  1237 }
  1269 % }
  1238 
  1270 % 
  1239 \paragraph{We are not able to fill this gap,} until we have to live
  1271 % \paragraph{We are not able to fill this gap,} until we have to live
  1240 with it but first have a look on the meaning of this statement:
  1272 % with it but first have a look on the meaning of this statement:
  1241 Mechanized math starts from mathematical models and \emph{hopefully}
  1273 % Mechanized math starts from mathematical models and \emph{hopefully}
  1242 proceeds to match physics. Academic engineering starts from physics
  1274 % proceeds to match physics. Academic engineering starts from physics
  1243 (experimentation, measurement) and then proceeds to mathematical
  1275 % (experimentation, measurement) and then proceeds to mathematical
  1244 modeling and formalization. The process from a physical observance to
  1276 % modeling and formalization. The process from a physical observance to
  1245 a mathematical theory is unavoidable bound of setting up a big
  1277 % a mathematical theory is unavoidable bound of setting up a big
  1246 collection of standards, rules, definition but also exceptions. These
  1278 % collection of standards, rules, definition but also exceptions. These
  1247 are the things making mechanization that difficult.
  1279 % are the things making mechanization that difficult.
  1248 
  1280 % 
  1249 \vbox{
  1281 % \vbox{
  1250   \begin{example}
  1282 %   \begin{example}
  1251     \label{eg:units}
  1283 %     \label{eg:units}
  1252     \[
  1284 %     \[
  1253       m,\ kg,\ s,\ldots
  1285 %       m,\ kg,\ s,\ldots
  1254     \]
  1286 %     \]
  1255     {\small\textit{
  1287 %     {\small\textit{
  1256       \noindent Think about some units like that one's above. Behind
  1288 %       \noindent Think about some units like that one's above. Behind
  1257 each unit there is a discerning and very accurate definition: One
  1289 % each unit there is a discerning and very accurate definition: One
  1258 Meter is the distance the light travels, in a vacuum, through the time
  1290 % Meter is the distance the light travels, in a vacuum, through the time
  1259 of 1 / 299.792.458 second; one kilogram is the weight of a
  1291 % of 1 / 299.792.458 second; one kilogram is the weight of a
  1260 platinum-iridium cylinder in paris; and so on. But are these
  1292 % platinum-iridium cylinder in paris; and so on. But are these
  1261 definitions usable in a computer mechanized world?!
  1293 % definitions usable in a computer mechanized world?!
  1262     }}
  1294 %     }}
  1263   \end{example}
  1295 %   \end{example}
  1264 }
  1296 % }
  1265 
  1297 % 
  1266 \paragraph{A computer} or a TP-System builds on programs with
  1298 % \paragraph{A computer} or a TP-System builds on programs with
  1267 predefined logical rules and does not know any mathematical trick
  1299 % predefined logical rules and does not know any mathematical trick
  1268 (follow up example \ref{eg:trick}) or recipe to walk around difficult
  1300 % (follow up example \ref{eg:trick}) or recipe to walk around difficult
  1269 expressions. 
  1301 % expressions. 
  1270 
  1302 % 
  1271 \vbox{
  1303 % \vbox{
  1272   \begin{example}
  1304 %   \begin{example}
  1273     \label{eg:trick}
  1305 %     \label{eg:trick}
  1274   \[ \frac{1}{j\omega}\cdot\left(e^{-j\omega}-e^{j3\omega}\right)= \]
  1306 %   \[ \frac{1}{j\omega}\cdot\left(e^{-j\omega}-e^{j3\omega}\right)= \]
  1275   \[ \frac{1}{j\omega}\cdot e^{-j2\omega}\cdot\left(e^{j\omega}-e^{-j\omega}\right)=
  1307 %   \[ \frac{1}{j\omega}\cdot e^{-j2\omega}\cdot\left(e^{j\omega}-e^{-j\omega}\right)=
  1276      \frac{1}{\omega}\, e^{-j2\omega}\cdot\colorbox{lgray}{$\frac{1}{j}\,\left(e^{j\omega}-e^{-j\omega}\right)$}= \]
  1308 %      \frac{1}{\omega}\, e^{-j2\omega}\cdot\colorbox{lgray}{$\frac{1}{j}\,\left(e^{j\omega}-e^{-j\omega}\right)$}= \]
  1277   \[ \frac{1}{\omega}\, e^{-j2\omega}\cdot\colorbox{lgray}{$2\, sin(\omega)$} \]
  1309 %   \[ \frac{1}{\omega}\, e^{-j2\omega}\cdot\colorbox{lgray}{$2\, sin(\omega)$} \]
  1278     {\small\textit{
  1310 %     {\small\textit{
  1279       \noindent Sometimes it is also useful to be able to apply some
  1311 %       \noindent Sometimes it is also useful to be able to apply some
  1280 \emph{tricks} to get a beautiful and particularly meaningful result,
  1312 % \emph{tricks} to get a beautiful and particularly meaningful result,
  1281 which we are able to interpret. But as seen in this example it can be
  1313 % which we are able to interpret. But as seen in this example it can be
  1282 hard to find out what operations have to be done to transform a result
  1314 % hard to find out what operations have to be done to transform a result
  1283 into a meaningful one.
  1315 % into a meaningful one.
  1284     }}
  1316 %     }}
  1285   \end{example}
  1317 %   \end{example}
  1286 }
  1318 % }
  1287 
  1319 % 
  1288 \paragraph{The only possibility,} for such a system, is to work
  1320 % \paragraph{The only possibility,} for such a system, is to work
  1289 through its known definitions and stops if none of these
  1321 % through its known definitions and stops if none of these
  1290 fits. Specified on Signal Processing or any other application it is
  1322 % fits. Specified on Signal Processing or any other application it is
  1291 often possible to walk through by doing simple creases. This creases
  1323 % often possible to walk through by doing simple creases. This creases
  1292 are in general based on simple math operational but the challenge is
  1324 % are in general based on simple math operational but the challenge is
  1293 to teach the machine \emph{all}\footnote{Its pride to call it
  1325 % to teach the machine \emph{all}\footnote{Its pride to call it
  1294 \emph{all}.} of them. Unfortunately the goal of TP Isabelle is to
  1326 % \emph{all}.} of them. Unfortunately the goal of TP Isabelle is to
  1295 reach a high level of \emph{all} but it in real it will still be a
  1327 % reach a high level of \emph{all} but it in real it will still be a
  1296 survey of knowledge which links to other knowledge and {{\sisac}{}} a
  1328 % survey of knowledge which links to other knowledge and {{\sisac}{}} a
  1297 trainer and helper but no human compensating calculator. 
  1329 % trainer and helper but no human compensating calculator. 
  1298 \par
  1330 % \par
  1299 {{{\sisac}{}}} itself aims to adds \emph{Algorithmic Knowledge} (formal
  1331 % {{{\sisac}{}}} itself aims to adds \emph{Algorithmic Knowledge} (formal
  1300 specifications of problems out of topics from Signal Processing, etc.)
  1332 % specifications of problems out of topics from Signal Processing, etc.)
  1301 and \emph{Application-oriented Knowledge} to the \emph{deductive} axis of
  1333 % and \emph{Application-oriented Knowledge} to the \emph{deductive} axis of
  1302 physical knowledge. The result is a three-dimensional universe of
  1334 % physical knowledge. The result is a three-dimensional universe of
  1303 mathematics seen in Figure~\ref{fig:mathuni}.
  1335 % mathematics seen in Figure~\ref{fig:mathuni}.
  1304 
  1336 % 
  1305 \begin{figure}
  1337 % \begin{figure}
  1306   \begin{center}
  1338 %   \begin{center}
  1307     \includegraphics{fig/universe}
  1339 %     \includegraphics{fig/universe}
  1308     \caption{Didactic ``Math-Universe'': Algorithmic Knowledge (Programs) is
  1340 %     \caption{Didactic ``Math-Universe'': Algorithmic Knowledge (Programs) is
  1309              combined with Application-oriented Knowledge (Specifications) and Deductive Knowledge (Axioms, Definitions, Theorems). The Result
  1341 %              combined with Application-oriented Knowledge (Specifications) and Deductive Knowledge (Axioms, Definitions, Theorems). The Result
  1310              leads to a three dimensional math universe.\label{fig:mathuni}}
  1342 %              leads to a three dimensional math universe.\label{fig:mathuni}}
  1311   \end{center}
  1343 %   \end{center}
  1312 \end{figure}
  1344 % \end{figure}
  1313 
  1345 % 
  1314 %WN Deine aktuelle Benennung oben wird Dir kein Fachmann abnehmen;
  1346 % %WN Deine aktuelle Benennung oben wird Dir kein Fachmann abnehmen;
  1315 %WN bitte folgende Bezeichnungen nehmen:
  1347 % %WN bitte folgende Bezeichnungen nehmen:
  1316 %WN 
  1348 % %WN 
  1317 %WN axis 1: Algorithmic Knowledge (Programs)
  1349 % %WN axis 1: Algorithmic Knowledge (Programs)
  1318 %WN axis 2: Application-oriented Knowledge (Specifications)
  1350 % %WN axis 2: Application-oriented Knowledge (Specifications)
  1319 %WN axis 3: Deductive Knowledge (Axioms, Definitions, Theorems)
  1351 % %WN axis 3: Deductive Knowledge (Axioms, Definitions, Theorems)
  1320 %WN 
  1352 % %WN 
  1321 %WN und bitte die R"ander von der Grafik wegschneiden (was ich f"ur *.pdf
  1353 % %WN und bitte die R"ander von der Grafik wegschneiden (was ich f"ur *.pdf
  1322 %WN nicht hinkriege --- weshalb ich auch die eJMT-Forderung nicht ganz
  1354 % %WN nicht hinkriege --- weshalb ich auch die eJMT-Forderung nicht ganz
  1323 %WN verstehe, separierte PDFs zu schicken; ich w"urde *.png schicken)
  1355 % %WN verstehe, separierte PDFs zu schicken; ich w"urde *.png schicken)
  1324 
  1356 % 
  1325 %JR Ränder und beschriftung geändert. Keine Ahnung warum eJMT sich pdf's
  1357 % %JR Ränder und beschriftung geändert. Keine Ahnung warum eJMT sich pdf's
  1326 %JR wünschen, würde ebenfalls png oder ähnliches verwenden, aber wenn pdf's
  1358 % %JR wünschen, würde ebenfalls png oder ähnliches verwenden, aber wenn pdf's
  1327 %JR gefordert werden WN2...
  1359 % %JR gefordert werden WN2...
  1328 %WN2 meiner Meinung nach hat sich eJMT unklar ausgedr"uckt (z.B. kann
  1360 % %WN2 meiner Meinung nach hat sich eJMT unklar ausgedr"uckt (z.B. kann
  1329 %WN2 man meines Wissens pdf-figures nicht auf eine bestimmte Gr"osse
  1361 % %WN2 man meines Wissens pdf-figures nicht auf eine bestimmte Gr"osse
  1330 %WN2 zusammenschneiden um die R"ander weg zu bekommen)
  1362 % %WN2 zusammenschneiden um die R"ander weg zu bekommen)
  1331 %WN2 Mein Vorschlag ist, in umserem tex-file bei *.png zu bleiben und
  1363 % %WN2 Mein Vorschlag ist, in umserem tex-file bei *.png zu bleiben und
  1332 %WN2 png + pdf figures mitzuschicken.
  1364 % %WN2 png + pdf figures mitzuschicken.
  1333 
  1365 % 
  1334 \subsection{Notes on Problems with Traditional Notation}
  1366 % \subsection{Notes on Problems with Traditional Notation}
  1335 
  1367 % 
  1336 \paragraph{During research} on these topic severely problems on
  1368 % \paragraph{During research} on these topic severely problems on
  1337 traditional notations have been discovered. Some of them have been
  1369 % traditional notations have been discovered. Some of them have been
  1338 known in computer science for many years now and are still unsolved,
  1370 % known in computer science for many years now and are still unsolved,
  1339 one of them aggregates with the so called \emph{Lambda Calculus},
  1371 % one of them aggregates with the so called \emph{Lambda Calculus},
  1340 Example~\ref{eg:lamda} provides a look on the problem that embarrassed
  1372 % Example~\ref{eg:lamda} provides a look on the problem that embarrassed
  1341 us.
  1373 % us.
  1342 
  1374 % 
  1343 \vbox{
  1375 % \vbox{
  1344   \begin{example}
  1376 %   \begin{example}
  1345     \label{eg:lamda}
  1377 %     \label{eg:lamda}
  1346 
  1378 % 
  1347   \[ f(x)=\ldots\;  \quad R \rightarrow \quad R \]
  1379 %   \[ f(x)=\ldots\;  \quad R \rightarrow \quad R \]
  1348 
  1380 % 
  1349 
  1381 % 
  1350   \[ f(p)=\ldots\;  p \in \quad R \]
  1382 %   \[ f(p)=\ldots\;  p \in \quad R \]
  1351 
  1383 % 
  1352     {\small\textit{
  1384 %     {\small\textit{
  1353       \noindent Above we see two equations. The first equation aims to
  1385 %       \noindent Above we see two equations. The first equation aims to
  1354 be a mapping of an function from the reel range to the reel one, but
  1386 % be a mapping of an function from the reel range to the reel one, but
  1355 when we change only one letter we get the second equation which
  1387 % when we change only one letter we get the second equation which
  1356 usually aims to insert a reel point $p$ into the reel function. In
  1388 % usually aims to insert a reel point $p$ into the reel function. In
  1357 computer science now we have the problem to tell the machine (TP) the
  1389 % computer science now we have the problem to tell the machine (TP) the
  1358 difference between this two notations. This Problem is called
  1390 % difference between this two notations. This Problem is called
  1359 \emph{Lambda Calculus}.
  1391 % \emph{Lambda Calculus}.
  1360     }}
  1392 %     }}
  1361   \end{example}
  1393 %   \end{example}
  1362 }
  1394 % }
  1363 
  1395 % 
  1364 \paragraph{An other problem} is that terms are not full simplified in
  1396 % \paragraph{An other problem} is that terms are not full simplified in
  1365 traditional notations, in {{\sisac}} we have to simplify them complete
  1397 % traditional notations, in {{\sisac}} we have to simplify them complete
  1366 to check weather results are compatible or not. in e.g. the solutions
  1398 % to check weather results are compatible or not. in e.g. the solutions
  1367 of an second order linear equation is an rational in {{\sisac}} but in
  1399 % of an second order linear equation is an rational in {{\sisac}} but in
  1368 tradition we keep fractions as long as possible and as long as they
  1400 % tradition we keep fractions as long as possible and as long as they
  1369 aim to be \textit{beautiful} (1/8, 5/16,...).
  1401 % aim to be \textit{beautiful} (1/8, 5/16,...).
  1370 \subparagraph{The math} which should be mechanized in Computer Theorem
  1402 % \subparagraph{The math} which should be mechanized in Computer Theorem
  1371 Provers (\emph{TP}) has (almost) a problem with traditional notations
  1403 % Provers (\emph{TP}) has (almost) a problem with traditional notations
  1372 (predicate calculus) for axioms, definitions, lemmas, theorems as a
  1404 % (predicate calculus) for axioms, definitions, lemmas, theorems as a
  1373 computer program or script is not able to interpret every Greek or
  1405 % computer program or script is not able to interpret every Greek or
  1374 Latin letter and every Greek, Latin or whatever calculations
  1406 % Latin letter and every Greek, Latin or whatever calculations
  1375 symbol. Also if we would be able to handle these symbols we still have
  1407 % symbol. Also if we would be able to handle these symbols we still have
  1376 a problem to interpret them at all. (Follow up \hbox{Example
  1408 % a problem to interpret them at all. (Follow up \hbox{Example
  1377 \ref{eg:symbint1}})
  1409 % \ref{eg:symbint1}})
  1378 
  1410 % 
  1379 \vbox{
  1411 % \vbox{
  1380   \begin{example}
  1412 %   \begin{example}
  1381     \label{eg:symbint1}
  1413 %     \label{eg:symbint1}
  1382     \[
  1414 %     \[
  1383       u\left[n\right] \ \ldots \ unitstep
  1415 %       u\left[n\right] \ \ldots \ unitstep
  1384     \]
  1416 %     \]
  1385     {\small\textit{
  1417 %     {\small\textit{
  1386       \noindent The unitstep is something we need to solve Signal
  1418 %       \noindent The unitstep is something we need to solve Signal
  1387 Processing problem classes. But in {{{\sisac}{}}} the rectangular
  1419 % Processing problem classes. But in {{{\sisac}{}}} the rectangular
  1388 brackets have a different meaning. So we abuse them for our
  1420 % brackets have a different meaning. So we abuse them for our
  1389 requirements. We get something which is not defined, but usable. The
  1421 % requirements. We get something which is not defined, but usable. The
  1390 Result is syntax only without semantic.
  1422 % Result is syntax only without semantic.
  1391     }}
  1423 %     }}
  1392   \end{example}
  1424 %   \end{example}
  1393 }
  1425 % }
  1394 
  1426 % 
  1395 In different problems, symbols and letters have different meanings and
  1427 % In different problems, symbols and letters have different meanings and
  1396 ask for different ways to get through. (Follow up \hbox{Example
  1428 % ask for different ways to get through. (Follow up \hbox{Example
  1397 \ref{eg:symbint2}}) 
  1429 % \ref{eg:symbint2}}) 
  1398 
  1430 % 
  1399 \vbox{
  1431 % \vbox{
  1400   \begin{example}
  1432 %   \begin{example}
  1401     \label{eg:symbint2}
  1433 %     \label{eg:symbint2}
  1402     \[
  1434 %     \[
  1403       \widehat{\ }\ \widehat{\ }\ \widehat{\ } \  \ldots \  exponent
  1435 %       \widehat{\ }\ \widehat{\ }\ \widehat{\ } \  \ldots \  exponent
  1404     \]
  1436 %     \]
  1405     {\small\textit{
  1437 %     {\small\textit{
  1406     \noindent For using exponents the three \texttt{widehat} symbols
  1438 %     \noindent For using exponents the three \texttt{widehat} symbols
  1407 are required. The reason for that is due the development of
  1439 % are required. The reason for that is due the development of
  1408 {{{\sisac}{}}} the single \texttt{widehat} and also the double were
  1440 % {{{\sisac}{}}} the single \texttt{widehat} and also the double were
  1409 already in use for different operations.
  1441 % already in use for different operations.
  1410     }}
  1442 %     }}
  1411   \end{example}
  1443 %   \end{example}
  1412 }
  1444 % }
  1413 
  1445 % 
  1414 \paragraph{Also the output} can be a problem. We are familiar with a
  1446 % \paragraph{Also the output} can be a problem. We are familiar with a
  1415 specified notations and style taught in university but a computer
  1447 % specified notations and style taught in university but a computer
  1416 program has no knowledge of the form proved by a professor and the
  1448 % program has no knowledge of the form proved by a professor and the
  1417 machines themselves also have not yet the possibilities to print every
  1449 % machines themselves also have not yet the possibilities to print every
  1418 symbol (correct) Recent developments provide proofs in a human
  1450 % symbol (correct) Recent developments provide proofs in a human
  1419 readable format but according to the fact that there is no money for
  1451 % readable format but according to the fact that there is no money for
  1420 good working formal editors yet, the style is one thing we have to
  1452 % good working formal editors yet, the style is one thing we have to
  1421 live with.
  1453 % live with.
  1422 
  1454 % 
  1423 \section{Problems rising out of the Development Environment}
  1455 % \section{Problems rising out of the Development Environment}
  1424 
  1456 % 
  1425 fehlermeldungen! TODO
  1457 % fehlermeldungen! TODO
  1426 
  1458 
  1427 \section{Conclusion}\label{conclusion}
  1459 \section{Conclusion}\label{conclusion}
  1428 
  1460 
  1429 TODO
  1461 TODO
  1430 
  1462