The Isabelle Logo

Versions

The logo is available for the generic Isabelle system (plain, transparent) and major object logics (ZF, HOL, HOLCF).

Interpretation

[Isabelle logo] First of all, the logo tells about the name of the generic system, Isabelle, or of its concrete instantiations, e.g. Isabelle/HOL. It also expresses some essentials of the overall Isabelle design philosophy: Composition of several small well understood building blocks, grouped together or arranged in layers.

The markings on the cubes illustrate this general principle by example of the core meta-logic (which is minimal higher-order logic on top of naively polymorphic simply typed lambda calculus). Thus red cubes symbolize the type system with function spaces (->) and type variables (alpha); violet ones represent the lambda term language with beta conversion etc.; yellow cubes constitute the actual logical parts, namely meta-implication or entailment (|-) and meta-level universal quantification.

Acknowledgment

The logo is contributed by Franziska Wenzel, Munich. It had been designed on Apple Macintosh.


[Isabelle logo]

[Isabelle logo (transparent)] Note: This may look bad on black and white displays.

[Isabelle logo
(ZF)]

[Isabelle logo
(HOL)]

[Isabelle logo
(HOLCF)]