author | oheimb |
Thu, 01 Feb 2001 20:51:48 +0100 | |
changeset 11025 | a70b796d9af8 |
parent 5078 | 7b5ea59c0275 |
child 11375 | a6730c90e753 |
permissions | -rw-r--r-- |
(* Title: HOL/Integ/Lagrange.thy ID: $Id$ Author: Tobias Nipkow Copyright 1996 TU Muenchen This theory only contains a single thm, which is a lemma in Lagrange's proof that every natural number is the sum of 4 squares. It's sole purpose is to demonstrate ordered rewriting for commutative rings. The enterprising reader might consider proving all of Lagrange's thm. *) Lagrange = Ring + constdefs sq :: 'a::times => 'a "sq x == x*x" end