Theorem equsb1 1191

Description: Substitution applied to an atomic wff.

Assertion

Ref	Expression
equsb1	|- [y / x]x = y

Proof of Theorem equsb1

Step	Hyp	Ref	Expression
1		sb2 1175	. 2 |- (A.x(x = y -> x = y) -> [y / x]x = y)
2		id 59	. 2 |- (x = y -> x = y)
3	1, 2	mpg 984	1 |- [y / x]x = y

Syntax hints:   -> wi 3   = wceq 954  [wsbc 1168

This theorem is referenced by:  sbequ8 1245  exss 2764

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-gen 961  ax-4 971  ax-5o 973  ax-6o 976  ax-9o 1121

This theorem depends on definitions:  df-bi 147  df-an 225  df-ex 979  df-sb 1170

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