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Date: Tue, 17 Apr 90 10:31:37 MDT
From: al@jupiter.nmt.edu (Al Stavely)
Message-Id: <9004171631.AA23175@jupiter.nmt.edu>
To: info-hol@clover.ucdavis.edu
Subject: need help with MATCH_MP_IMP_TAC

I'm a novice HOL user, working my way through the Tutorial, and I can't
get the case study in Chapter 9 to work.  I'm typing everything to HOL
as shown in the Tutorial, and I get the results shown up to the following
point (page 248):

----------------------------------------------------

#g "!n.NORMAL ((\N.T),$plus) (int_mult_set n)";;
#e (GEN_TAC THEN (MATCH_MP_IMP_TAC INT_SBGP_NORMAL));;
OK..
evaluation failed     dest_imp

----------------------------------------------------

The problem seems to be with MATCH_MP_IMP_TAC: there seems to be some kind
of a structure mismatch, so that it doesn't have the expected functionality.
I found another way to do this step of the proof, but MATCH_MP_IMP_TAC is
used several times in the case study, so I'd like to be able to use it.
It fails in the same way when I try it later, on page 257 of the Tutorial.

Before I start trying to patch things myself: does anyone know what's
happening?  Have the tutorial (dated December 8, 1989) and the group
theory library (part of the hol88.1.11 distribution) become incompatible
because of modifications?  I obtained both from Davis via anonymous ftp
on February 19.

Many thanks for any suggestions...

        - Allan Stavely    al@nmt.edu

