Theorem wa3 185

Description: Weak A3.

Assertion

Ref	Expression
wa3	(((a ∪ b) ∪ c) ≡ (a ∪ (b ∪ c))) = 1

Proof of Theorem wa3

Step	Hyp	Ref	Expression
1		ax-a3 31	. 2 ((a ∪ b) ∪ c) = (a ∪ (b ∪ c))
2	1	bi1 110	1 (((a ∪ b) ∪ c) ≡ (a ∪ (b ∪ c))) = 1

Syntax hints:   = wb 1   ≡ tb 5   ∪ wo 6  1wt 9

This theorem was proved from axioms:  ax-a1 29  ax-a2 30  ax-a3 31  ax-a5 33  ax-r1 34  ax-r2 35  ax-r4 36  ax-r5 37

This theorem depends on definitions:  df-b 38  df-a 39  df-t 40  df-f 41

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