Theorem difeq12d 3256

Description: Equality deduction for class difference. (Contributed by FL, 29-May-2014.)

Hypotheses

Ref	Expression
difeq12d.1	⊢ (𝜑 → 𝐴 = 𝐵)
difeq12d.2	⊢ (𝜑 → 𝐶 = 𝐷)

Assertion

Ref	Expression
difeq12d	⊢ (𝜑 → (𝐴 ∖ 𝐶) = (𝐵 ∖ 𝐷))

Proof of Theorem difeq12d

Step	Hyp	Ref	Expression
1		difeq12d.1	. . 3 ⊢ (𝜑 → 𝐴 = 𝐵)
2	1	difeq1d 3254	. 2 ⊢ (𝜑 → (𝐴 ∖ 𝐶) = (𝐵 ∖ 𝐶))
3		difeq12d.2	. . 3 ⊢ (𝜑 → 𝐶 = 𝐷)
4	3	difeq2d 3255	. 2 ⊢ (𝜑 → (𝐵 ∖ 𝐶) = (𝐵 ∖ 𝐷))
5	2, 4	eqtrd 2210	1 ⊢ (𝜑 → (𝐴 ∖ 𝐶) = (𝐵 ∖ 𝐷))

Syntax hints:   → wi 4   = wceq 1353   ∖ cdif 3128

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 614  ax-in2 615  ax-io 709  ax-5 1447  ax-7 1448  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-10 1505  ax-11 1506  ax-i12 1507  ax-bndl 1509  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159

This theorem depends on definitions:  df-bi 117  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-nfc 2308  df-ral 2460  df-rab 2464  df-dif 3133

This theorem is referenced by:  undifexmid  4195  exmidundif  4208  exmidundifim  4209