From 56c8eb03f3e549f8b97bc0e1e7aa51f393d92595 Mon Sep 17 00:00:00 2001 From: Chris Date: Mon, 16 Feb 2015 21:59:29 -0500 Subject: [PATCH 1/1] added disclaimer about revised lambda->CL map --- topics/week3_combinatory_logic.mdwn | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/topics/week3_combinatory_logic.mdwn b/topics/week3_combinatory_logic.mdwn index c15424f9..0ddb4469 100644 --- a/topics/week3_combinatory_logic.mdwn +++ b/topics/week3_combinatory_logic.mdwn @@ -175,6 +175,17 @@ used to establish a correspondence between two natural language grammars, one of which is based on lambda-like abstraction, the other of which is based on Combinatory Logic-like manipulations. +[WARNING: the mapping from the lambda calculus to Combinatory Logic +has been changed since the class in which it was presented. It now +matches the presentation in Barendregt. The revised version is +cleaner, and more elegant. If you spent a lot of time working to +understand the original version, there's good news and bad news. The +bad news is that things have changed. The good news is that the new +version described the same mapping as before, but does it in a cleaner +way. That is, the CL term that a given lambda term maps onto hasn't +changed, only the details of how that CL term gets computed. Sorry if +the changeup causes any distress!] + In order to establish the correspondence, we need to get a bit more official about what counts as an expression in CL. We'll endow CL with an infinite stock of variable symbols, just like the lambda -- 2.11.0