author desharna
Sat, 22 Jan 2022 14:33:35 +0100
changeset 75420 01bb90de56bb
parent 33686 8e33ca8832b1
permissions -rw-r--r--
optimized facts traversal in TPTP translation

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "">


  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
  <title>The Isabelle Logo</title>


<h1>The Isabelle Logo</h1>


The logo is available as bitmap file for the generic Isabelle system
(<a href="#plain">plain</a>, <a href="#transparent">transparent</a>)
and major object logics (<a href="#ZF">ZF</a>, <a href="#HOL">HOL</a>,
<a href="#HOLCF">HOLCF</a>).  There are also <a
href="isabelle-small.xpm">small</a> and <a
href="isabelle-tiny.xpm">tiny</a> Isabelle icons available.
Furthermore, scalable (EPS) versions of the logo may be generated for
any logic using the <tt>isabelle logo</tt> utility distributed with


<img src="isabelle.gif" align=right alt="[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. <p>

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 (-&gt;) 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.


The logo is contributed by <a
Wenzel</a>, Munich.  It has been designed on Apple Macintosh.


<a name="plain"><img src="isabelle.gif" alt="[Isabelle logo]"></a> <p>

<a name="transparent"><img src="isabelle_transparent.gif" alt="[Isabelle logo (transparent)]"></a> Note: This may look bad on
black and white displays. <p>

<a name="ZF"><img src="isabelle_zf.gif" alt="[Isabelle logo (ZF)]"></a> <p>

<a name="HOL"><img src="isabelle_hol.gif" alt="[Isabelle logo (HOL)]"></a> <p>

<a name="HOLCF"><img src="isabelle_holcf.gif" alt="[Isabelle logo (HOLCF)]"></a>