Theorem equsb2 1194

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 1177	. 2 |- (A.x(x = y -> y = x) -> [y / x]y = x)
2		equcomi 1128	. 2 |- (x = y -> y = x)
3	1, 2	mpg 986	1 |- [y / x]y = x

Syntax hints:   -> wi 3   = wceq 956  [wsbc 1170

This theorem is referenced by:  sbco 1252  equsb3lem 1329  elsb3 1331

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-gen 963  ax-8 964  ax-12 968  ax-4 973  ax-5o 975  ax-6o 978  ax-9o 1123

This theorem depends on definitions:  df-bi 147  df-an 225  df-ex 981  df-sb 1172

Copyright terms: Public domain