| author | wenzelm |
| Fri, 25 Apr 1997 17:50:55 +0200 | |
| changeset 3061 | 25b2a895f864 |
| parent 2281 | e00c13a29eda |
| 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