Theorem difeq12i 4072

Description: Equality inference for class difference. (Contributed by NM, 29-Aug-2004.)

Hypotheses

Ref	Expression
difeq1i.1	⊢ 𝐴 = 𝐵
difeq12i.2	⊢ 𝐶 = 𝐷

Assertion

Ref	Expression
difeq12i	⊢ (𝐴 ∖ 𝐶) = (𝐵 ∖ 𝐷)

Proof of Theorem difeq12i

Step	Hyp	Ref	Expression
1		difeq1i.1	. . 3 ⊢ 𝐴 = 𝐵
2	1	difeq1i 4070	. 2 ⊢ (𝐴 ∖ 𝐶) = (𝐵 ∖ 𝐶)
3		difeq12i.2	. . 3 ⊢ 𝐶 = 𝐷
4	3	difeq2i 4071	. 2 ⊢ (𝐵 ∖ 𝐶) = (𝐵 ∖ 𝐷)
5	2, 4	eqtri 2784	1 ⊢ (𝐴 ∖ 𝐶) = (𝐵 ∖ 𝐷)

This proof depends on syntax axioms:   = wceq 1570   ∖ cdif 3896

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 2147  ax-9 2155  ax-ext 2733

This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-sb 2100  df-clab 2740  df-cleq 2753  df-clel 2836  df-rab 3414  df-dif 3902

This theorem is used by:  indifdir  4241  difrab  4264  resdifdi  6237  resdifdir  6238  preddif  6332  infdju1  10268  uniioombllem4  25907  new0  28250  clwwlknclwwlkdif  30570  gtiso  33294  satffunlem2lem2  36171  mthmpps  36347  zrdivrng  38887  isdrngo1  38890  pwfi2f1o  44097  salexct2  47348  dfnelbr2  48342