From paul@tina  Thu Dec  7 13:17:42 1989
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Date: Thu, 7 Dec 89 13:18:14 PST
From: paul@tina.stanford.edu (Paul N. Loewenstein)
Message-Id: <8912072118.AA17417@tina>
To: info-hol@clover.ucdavis.edu
Subject: Lists with elements of varying types


Surely LISP-style lists are equivalent to HOL-style lists where the
element type is a disjoint sum. The LISP equivalents of appropriate
applications of ISL and ISR are NUMBERP LISTP ......

The problem arises that as more types are added to the system, the
list element type has to be redefined. In LISP this "happens"
invisibly whenever a new type is defined.


