1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2 3<html> 4 5<head> 6 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> 7 <title>The Isabelle Logo</title> 8</head> 9 10<body> 11 12<h1>The Isabelle Logo</h1> 13 14<h2>Versions</h2> 15 16The logo is available as bitmap file for the generic Isabelle system 17(<a href="#plain">plain</a>, <a href="#transparent">transparent</a>) 18and major object logics (<a href="#ZF">ZF</a>, <a href="#HOL">HOL</a>, 19<a href="#HOLCF">HOLCF</a>). There are also <a 20href="isabelle-small.xpm">small</a> and <a 21href="isabelle-tiny.xpm">tiny</a> Isabelle icons available. 22Furthermore, scalable (EPS) versions of the logo may be generated for 23any logic using the <tt>isabelle logo</tt> utility distributed with 24Isabelle. 25 26 27<h2>Interpretation</h2> 28 29<img src="isabelle.gif" align=right alt="[Isabelle logo]"> First of 30all, the logo tells about the name of the generic system, Isabelle, or 31of its concrete instantiations, e.g. Isabelle/HOL. It also expresses 32some essentials of the overall Isabelle design philosophy: Composition 33of several small well understood building blocks, grouped together or 34arranged in layers. <p> 35 36The markings on the cubes illustrate this general principle by example 37of the core meta-logic (which is minimal higher-order logic on top of 38naively polymorphic simply typed lambda calculus). Thus red cubes 39symbolize the type system with function spaces (->) and type 40variables (alpha); violet ones represent the lambda term language with 41beta conversion etc.; yellow cubes constitute the actual logical 42parts, namely meta-implication or entailment (|-) and meta-level 43universal quantification. 44 45 46<h2>Acknowledgment</h2> 47 48The logo is contributed by <a 49href="http://www.informatik.tu-muenchen.de/~wenzel/">Franziska 50Wenzel</a>, Munich. It has been designed on Apple Macintosh. 51 52 53<p><hr><p> 54 55<a name="plain"><img src="isabelle.gif" alt="[Isabelle logo]"></a> <p> 56 57<a name="transparent"><img src="isabelle_transparent.gif" alt="[Isabelle logo (transparent)]"></a> Note: This may look bad on 58black and white displays. <p> 59 60<a name="ZF"><img src="isabelle_zf.gif" alt="[Isabelle logo (ZF)]"></a> <p> 61 62<a name="HOL"><img src="isabelle_hol.gif" alt="[Isabelle logo (HOL)]"></a> <p> 63 64<a name="HOLCF"><img src="isabelle_holcf.gif" alt="[Isabelle logo (HOLCF)]"></a> 65 66</body> 67</html> 68