Theorem eqelssd 3261

Description: Equality deduction from subclass relationship and membership. (Contributed by AV, 21-Aug-2022.)

Hypotheses

Ref	Expression
eqelssd.1	⊢ (𝜑 → 𝐴 ⊆ 𝐵)
eqelssd.2	⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → 𝑥 ∈ 𝐴)

Assertion

Ref	Expression
eqelssd	⊢ (𝜑 → 𝐴 = 𝐵)

Distinct variable groups:   𝑥,𝐴   𝑥,𝐵   𝜑,𝑥

Proof of Theorem eqelssd

Step	Hyp	Ref	Expression
1		eqelssd.1	. 2 ⊢ (𝜑 → 𝐴 ⊆ 𝐵)
2		eqelssd.2	. . . 4 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → 𝑥 ∈ 𝐴)
3	2	ex 115	. . 3 ⊢ (𝜑 → (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐴))
4	3	ssrdv 3248	. 2 ⊢ (𝜑 → 𝐵 ⊆ 𝐴)
5	1, 4	eqssd 3259	1 ⊢ (𝜑 → 𝐴 = 𝐵)

Syntax hints:   → wi 4   ∧ wa 104   = wceq 1398   ∈ wcel 2205   ⊆ wss 3214

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 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-11 1555  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-ext 2216

This theorem depends on definitions:  df-bi 117  df-nf 1510  df-sb 1812  df-clab 2221  df-cleq 2227  df-clel 2230  df-in 3220  df-ss 3227

This theorem is referenced by:  fiuni  7278  ennnfonelemrn  13254  ennnfonelemdm  13255  unirnblps  15413  unirnbl  15414  dvidlemap  15682  dvidrelem  15683  dvidsslem  15684  dviaddf  15696  dvimulf  15697  dvcj  15700  dvrecap  15704