Theorem sseq2i 3254

Description: An equality inference for the subclass relationship. (Contributed by NM, 30-Aug-1993.)

Hypothesis

Ref	Expression
sseq1i.1	⊢ 𝐴 = 𝐵

Assertion

Ref	Expression
sseq2i	⊢ (𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵)

Proof of Theorem sseq2i

Step	Hyp	Ref	Expression
1		sseq1i.1	. 2 ⊢ 𝐴 = 𝐵
2		sseq2 3251	. 2 ⊢ (𝐴 = 𝐵 → (𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵))
3	1, 2	ax-mp 5	1 ⊢ (𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵)

Syntax hints:   ↔ wb 105   = wceq 1397   ⊆ wss 3200

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-5 1495  ax-7 1496  ax-gen 1497  ax-ie1 1541  ax-ie2 1542  ax-8 1552  ax-11 1554  ax-4 1558  ax-17 1574  ax-i9 1578  ax-ial 1582  ax-i5r 1583  ax-ext 2213

This theorem depends on definitions:  df-bi 117  df-nf 1509  df-sb 1811  df-clab 2218  df-cleq 2224  df-clel 2227  df-in 3206  df-ss 3213

This theorem is referenced by:  sseqtri  3261  sseqtrdi  3275  abss  3296  ssrab  3305  ssintrab  3951  iunpwss  4062  iotass  5304  dffun2  5336  ssimaex  5707  pw1fin  7101  pw1dc0el  7102  ss1o0el1o  7104  isstructim  13095  isstructr  13096  issubm  13554  grpissubg  13780  issubrng  14212  umgredg  15995  bj-ssom  16531  ss1oel2o  16586