Theorem neeq12i 2262

Description: Inference for inequality. (Contributed by NM, 24-Jul-2012.)

Hypotheses

Ref	Expression
neeq1i.1	⊢ 𝐴 = 𝐵
neeq12i.2	⊢ 𝐶 = 𝐷

Assertion

Ref	Expression
neeq12i	⊢ (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐷)

Proof of Theorem neeq12i

Step	Hyp	Ref	Expression
1		neeq12i.2	. . 3 ⊢ 𝐶 = 𝐷
2	1	neeq2i 2261	. 2 ⊢ (𝐴 ≠ 𝐶 ↔ 𝐴 ≠ 𝐷)
3		neeq1i.1	. . 3 ⊢ 𝐴 = 𝐵
4	3	neeq1i 2260	. 2 ⊢ (𝐴 ≠ 𝐷 ↔ 𝐵 ≠ 𝐷)
5	2, 4	bitri 182	1 ⊢ (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐷)

Syntax hints:   ↔ wb 103   = wceq 1284   ≠ wne 2245

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-5 1376  ax-gen 1378  ax-4 1440  ax-17 1459  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-cleq 2074  df-ne 2246

This theorem is referenced by:  3netr3g  2279  3netr4g  2280