Theorem equsb2 1193

Description: Substitution applied to an atomic wff.

Assertion

Ref	Expression
equsb2	|- [y / x]y = x

Proof of Theorem equsb2

Step	Hyp	Ref	Expression
1		sb2 1176	. 2 |- (A.x(x = y -> y = x) -> [y / x]y = x)
2		equcomi 1127	. 2 |- (x = y -> y = x)
3	1, 2	mpg 985	1 |- [y / x]y = x

Syntax hints:   -> wi 3   = wceq 955  [wsbc 1169

This theorem is referenced by:  sbco 1251  equsb3lem 1328  elsb3 1330

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

This theorem depends on definitions:  df-bi 147  df-an 225  df-ex 980  df-sb 1171

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