Theorem eqneltri 2833

Description: If a class is not an element of another class, an equal class is also not an element. (Contributed by Glauco Siliprandi, 3-Jan-2021.)

Hypotheses

Ref	Expression
eqneltri.1	⊢ 𝐴 = 𝐵
eqneltri.2	⊢ ¬ 𝐵 ∈ 𝐶

Assertion

Ref	Expression
eqneltri	⊢ ¬ 𝐴 ∈ 𝐶

Proof of Theorem eqneltri

Step	Hyp	Ref	Expression
1		eqneltri.2	. 2 ⊢ ¬ 𝐵 ∈ 𝐶
2		eqneltri.1	. . 3 ⊢ 𝐴 = 𝐵
3	2	eleq1i 2830	. 2 ⊢ (𝐴 ∈ 𝐶 ↔ 𝐵 ∈ 𝐶)
4	1, 3	mtbir 322	1 ⊢ ¬ 𝐴 ∈ 𝐶

Syntax hints:  ¬ wn 3   = wceq 1541   ∈ wcel 2109

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1801  ax-4 1815  ax-5 1916  ax-6 1974  ax-7 2014  ax-8 2111  ax-9 2119  ax-ext 2710

This theorem depends on definitions:  df-bi 206  df-an 396  df-ex 1786  df-cleq 2731  df-clel 2817

This theorem is referenced by:  iprc  7747  tfr2b  8211  tz7.48-3  8259  pnfnre  11000  mnfnre  11002  prmrec  16604  00lsp  20224  goaln0  33334  bj-pinftynrr  35372  bj-minftynrr  35376  eliuniincex  42612  eliincex  42613  salgencntex  43836  nfermltl2rev  45147