Theorem necon3bii 2378

Description: Inference from equality to inequality. (Contributed by NM, 23-Feb-2005.)

Hypothesis

Ref	Expression
necon3bii.1	⊢ (𝐴 = 𝐵 ↔ 𝐶 = 𝐷)

Assertion

Ref	Expression
necon3bii	⊢ (𝐴 ≠ 𝐵 ↔ 𝐶 ≠ 𝐷)

Proof of Theorem necon3bii

Step	Hyp	Ref	Expression
1		necon3bii.1	. . 3 ⊢ (𝐴 = 𝐵 ↔ 𝐶 = 𝐷)
2	1	necon3abii 2376	. 2 ⊢ (𝐴 ≠ 𝐵 ↔ ¬ 𝐶 = 𝐷)
3		df-ne 2341	. 2 ⊢ (𝐶 ≠ 𝐷 ↔ ¬ 𝐶 = 𝐷)
4	2, 3	bitr4i 186	1 ⊢ (𝐴 ≠ 𝐵 ↔ 𝐶 ≠ 𝐷)

Syntax hints:  ¬ wn 3   ↔ wb 104   = wceq 1348   ≠ wne 2340

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 609  ax-in2 610

This theorem depends on definitions:  df-bi 116  df-ne 2341

This theorem is referenced by:  necom  2424  negne0bi  8192