Theorem eqsstrrdi 3280

Description: A chained subclass and equality deduction. (Contributed by Mario Carneiro, 2-Jan-2017.)

Hypotheses

Ref	Expression
eqsstrrdi.1	⊢ (𝜑 → 𝐵 = 𝐴)
eqsstrrdi.2	⊢ 𝐵 ⊆ 𝐶

Assertion

Ref	Expression
eqsstrrdi	⊢ (𝜑 → 𝐴 ⊆ 𝐶)

Proof of Theorem eqsstrrdi

Step	Hyp	Ref	Expression
1		eqsstrrdi.1	. . 3 ⊢ (𝜑 → 𝐵 = 𝐴)
2	1	eqcomd 2237	. 2 ⊢ (𝜑 → 𝐴 = 𝐵)
3		eqsstrrdi.2	. 2 ⊢ 𝐵 ⊆ 𝐶
4	2, 3	eqsstrdi 3279	1 ⊢ (𝜑 → 𝐴 ⊆ 𝐶)

Syntax hints:   → wi 4   = 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:  ffvresb  5810  tposss  6411  sbthlemi5  7159  iooval2  10149  telfsumo  12026  structcnvcnv  13097  ressbasssd  13151  txss12  14989  txbasval  14990