Theorem difeq2i 3087

Description: Inference adding difference to the left in a class equality. (Contributed by NM, 15-Nov-2002.)

Hypothesis

Ref	Expression
difeq1i.1	⊢ 𝐴 = 𝐵

Assertion

Ref	Expression
difeq2i	⊢ (𝐶 ∖ 𝐴) = (𝐶 ∖ 𝐵)

Proof of Theorem difeq2i

Step	Hyp	Ref	Expression
1		difeq1i.1	. 2 ⊢ 𝐴 = 𝐵
2		difeq2 3084	. 2 ⊢ (𝐴 = 𝐵 → (𝐶 ∖ 𝐴) = (𝐶 ∖ 𝐵))
3	1, 2	ax-mp 7	1 ⊢ (𝐶 ∖ 𝐴) = (𝐶 ∖ 𝐵)

Syntax hints:   = wceq 1284   ∖ cdif 2970

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-11 1437  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468  ax-ext 2063

This theorem depends on definitions:  df-bi 115  df-tru 1287  df-nf 1390  df-sb 1686  df-clab 2068  df-cleq 2074  df-clel 2077  df-ral 2353  df-rab 2357  df-dif 2975

This theorem is referenced by:  difeq12i  3088  inssddif  3205  difdif2ss  3221  dif32  3227  difabs  3228  symdif1  3229  notrab  3241  dif0  3314  difdifdirss  3327  dfif3  3364  dif1o  6044