ex/lexprod.thy

HOL/HOL.ML/selectI2: new rule for descriptions

(*  Title: 	HOL/ex/lex-prod.thy
    ID:         $Id$
    Author: 	Tobias Nipkow, TU Munich
    Copyright   1993  TU Munich

The lexicographic product of two relations.
*)

LexProd = WF + Prod +
consts "**" :: "[('a*'a)set, ('b*'b)set] => (('a*'b)*('a*'b))set" (infixl 70)
rules
lex_prod_def "ra**rb == {p. ? a a' b b'. \
\	p = <<a,b>,<a',b'>> & (<a,a'> : ra | a=a' & <b,b'> : rb)}"
end