Theorem u4lemc3 694

Description: Commutation theorem for non-tollens implication.

Hypothesis

Ref	Expression
ulemc3.1	a C b

Assertion

Ref	Expression
u4lemc3	a C (b ->4 a)

Proof of Theorem u4lemc3

Step	Hyp	Ref	Expression
1		u4lemc1 683	1 a C (b ->4 a)

Syntax hints:   C wc 3   ->4 wi4 15

This theorem was proved from axioms:  ax-a1 30  ax-a2 31  ax-a3 32  ax-a4 33  ax-a5 34  ax-r1 35  ax-r2 36  ax-r4 37  ax-r5 38  ax-r3 439

This theorem depends on definitions:  df-b 39  df-a 40  df-t 41  df-f 42  df-i4 47  df-le1 130  df-le2 131  df-c1 132  df-c2 133

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