Theorem necon2ai 2414

Description: Contrapositive inference for inequality. (Contributed by NM, 16-Jan-2007.) (Proof rewritten by Jim Kingdon, 16-May-2018.)

Hypothesis

Ref	Expression
necon2ai.1	⊢ (𝐴 = 𝐵 → ¬ 𝜑)

Assertion

Ref	Expression
necon2ai	⊢ (𝜑 → 𝐴 ≠ 𝐵)

Proof of Theorem necon2ai

Step	Hyp	Ref	Expression
1		necon2ai.1	. . 3 ⊢ (𝐴 = 𝐵 → ¬ 𝜑)
2	1	con2i 628	. 2 ⊢ (𝜑 → ¬ 𝐴 = 𝐵)
3		df-ne 2361	. 2 ⊢ (𝐴 ≠ 𝐵 ↔ ¬ 𝐴 = 𝐵)
4	2, 3	sylibr 134	1 ⊢ (𝜑 → 𝐴 ≠ 𝐵)

Syntax hints:  ¬ wn 3   → wi 4   = wceq 1364   ≠ wne 2360

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616

This theorem depends on definitions:  df-bi 117  df-ne 2361

This theorem is referenced by:  necon2i  2416  neneqad  2439  intexr  4165  iin0r  4184  tfrlemisucaccv  6344  pm54.43  7207  renepnf  8023  renemnf  8024  lt0ne0d  8488  nnne0  8965  nn0nepnf  9265  hashennn  10778  bj-intexr  15057