From e91f395c588c28cca8c9f73798d7d3f2c8a03d91 Mon Sep 17 00:00:00 2001 From: Jim Pryor Date: Wed, 15 Sep 2010 21:24:21 -0400 Subject: [PATCH] Revert "week1: tweaks" This reverts commit 1a51e3f913eae290c6d345cfa0d1cd31bdfeea1f. --- week1.mdwn | 2 -- 1 file changed, 2 deletions(-) diff --git a/week1.mdwn b/week1.mdwn index 249bc1e2..09ad8bd1 100644 --- a/week1.mdwn +++ b/week1.mdwn @@ -56,8 +56,6 @@ It's possible to enhance the lambda calculus so that functions do get identified It's often said that dynamic systems are distinguished because they are the ones in which **order matters**. However, there are many ways in which order can matter. If we have a trivalent boolean system, for example---easily had in a purely functional calculus---we might choose TODO - true and true = true - And then we'd notice that * and false has a different intepretation than false and *. (The same phenomenon is already present with the material conditional in bivalent logics; but seeing that a non-symmetric semantics for `and` is available even for functional languages is instructive.) Another way in which order can matter that's present even in functional languages is that the interpretation of some complex expressions can depend on the order in which sub-expressions are evaluated. Evaluated in one order, the computations might never terminate (and so semantically we interpret them as having "the bottom value"---we'll discuss this). Evaluated in another order, they might have a perfectly mundane value. Here's an example, though we'll reserve discussion of it until later: -- 2.11.0