Theorem equtrr 1131

Description: A transitive law for equality. Lemma L17 in [Megill] p. 446 (p. 14 of the preprint).

Assertion

Ref	Expression
equtrr	|- (x = y -> (z = x -> z = y))

Proof of Theorem equtrr

Step	Hyp	Ref	Expression
1		equtr 1130	. 2 |- (z = x -> (x = y -> z = y))
2	1	com12 11	1 |- (x = y -> (z = x -> z = y))

Syntax hints:   -> wi 3   = wceq 955

This theorem is referenced by:  equequ2 1134  equvini 1167  ax11eq 1363

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-gen 962  ax-8 963  ax-12 967  ax-4 972  ax-5o 974  ax-6o 977  ax-9o 1122

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