Theorem necon2abid 2989

Description: Contrapositive deduction for inequality. (Contributed by NM, 18-Jul-2007.) (Proof shortened by Wolf Lammen, 24-Nov-2019.)

Hypothesis

Ref	Expression
necon2abid.1	⊢ (𝜑 → (𝐴 = 𝐵 ↔ ¬ 𝜓))

Assertion

Ref	Expression
necon2abid	⊢ (𝜑 → (𝜓 ↔ 𝐴 ≠ 𝐵))

Proof of Theorem necon2abid

Step	Hyp	Ref	Expression
1		notnotb 315	. 2 ⊢ (𝜓 ↔ ¬ ¬ 𝜓)
2		necon2abid.1	. . 3 ⊢ (𝜑 → (𝐴 = 𝐵 ↔ ¬ 𝜓))
3	2	necon3abid 2983	. 2 ⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ ¬ ¬ 𝜓))
4	1, 3	bitr4id 290	1 ⊢ (𝜑 → (𝜓 ↔ 𝐴 ≠ 𝐵))

Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 206   = wceq 1537   ≠ wne 2946

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 207  df-ne 2947

This theorem is referenced by:  sossfld  6217  funeldmb  7395  fin23lem24  10391  isf32lem4  10425  sqgt0sr  11175  leltne  11379  xrleltne  13207  xrltne  13225  ge0nemnf  13235  xlt2add  13322  supxrbnd  13390  supxrre2  13393  ioopnfsup  13915  icopnfsup  13916  xblpnfps  24426  xblpnf  24427  nmoreltpnf  30801  nmopreltpnf  31901  elprneb  46944