Theorem sseq2i 3051

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 3048	. 2 ⊢ (𝐴 = 𝐵 → (𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵))
3	1, 2	ax-mp 7	1 ⊢ (𝐶 ⊆ 𝐴 ↔ 𝐶 ⊆ 𝐵)

Syntax hints:   ↔ wb 103   = wceq 1289   ⊆ wss 2999

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-5 1381  ax-7 1382  ax-gen 1383  ax-ie1 1427  ax-ie2 1428  ax-8 1440  ax-11 1442  ax-4 1445  ax-17 1464  ax-i9 1468  ax-ial 1472  ax-i5r 1473  ax-ext 2070

This theorem depends on definitions:  df-bi 115  df-nf 1395  df-sb 1693  df-clab 2075  df-cleq 2081  df-clel 2084  df-in 3005  df-ss 3012

This theorem is referenced by:  sseqtri  3058  syl6sseq  3072  abss  3090  ssrab  3099  ssintrab  3711  iunpwss  3820  iotass  4997  dffun2  5025  ssimaex  5365  isstructim  11508  isstructr  11509  bj-ssom  11831  ss1oel2o  11888