Theorem elneq 9570

Description: A class is not equal to any of its elements. (Contributed by AV, 14-Jun-2022.)

Assertion

Ref	Expression
elneq	⊢ (𝐴 ∈ 𝐵 → 𝐴 ≠ 𝐵)

Proof of Theorem elneq

Step	Hyp	Ref	Expression
1		elirr 9569	. 2 ⊢ ¬ 𝐵 ∈ 𝐵
2		nelelne 3061	. 2 ⊢ (¬ 𝐵 ∈ 𝐵 → (𝐴 ∈ 𝐵 → 𝐴 ≠ 𝐵))
3	1, 2	ax-mp 5	1 ⊢ (𝐴 ∈ 𝐵 → 𝐴 ≠ 𝐵)

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∈ wcel 2146   ≠ wne 2960

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148  ax-9 2156  ax-ext 2737  ax-sep 5259  ax-reg 9561

This proof depends on definitions:  df-bi 210  df-an 402  df-tru 1573  df-ex 1813  df-sb 2100  df-clab 2744  df-cleq 2757  df-clel 2840  df-ne 2961

This theorem is used by:  nelaneqOLDOLD  9573  preleqg  9591  dfac2b  10130  disjressuc2  39120  oaomoencom  44104  oenassex  44105  tfsconcat0b  44133