a,b,c:. nnsub(a;b+c) = nnsub(nnsub(a;b);c)

By:	RewriteOfThm Thm* all Thm* (a:hnum. all Thm* (a:hnum. (b:hnum. all(c:hnum. equal(sub(a,add(b,c)),sub(sub(a,b),c))))) (SimpsetC [`hol_to_nuprl`;`bequal`])

None

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