Theorem neleqtrrd 2295

Description: If a class is not an element of another class, it is also not an element of an equal class. Deduction form. (Contributed by David Moews, 1-May-2017.)

Hypotheses

Ref	Expression
neleqtrrd.1	|- ( ph -> -. C e. B )
neleqtrrd.2	|- ( ph -> A = B )

Assertion

Ref	Expression
neleqtrrd	|- ( ph -> -. C e. A )

Proof of Theorem neleqtrrd

Step	Hyp	Ref	Expression
1		neleqtrrd.1	. 2 |- ( ph -> -. C e. B )
2		neleqtrrd.2	. . 3 |- ( ph -> A = B )
3	2	eleq2d 2266	. 2 |- ( ph -> ( C e. A <-> C e. B ) )
4	1, 3	mtbird 674	1 |- ( ph -> -. C e. A )

Syntax hints:   -. wn 3   -> wi 4   = wceq 1364   e. wcel 2167

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  ax-5 1461  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-4 1524  ax-17 1540  ax-ial 1548  ax-ext 2178

This theorem depends on definitions:  df-bi 117  df-cleq 2189  df-clel 2192

This theorem is referenced by:  tfr1onlemsucaccv  6399  tfrcllemsucaccv  6412  zfz1isolemiso  10931  wrdlndm  10952