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Theorem ceqsex2v 2896

Description: Elimination of two existential quantifiers, using implicit substitution. (Contributed by Scott Fenton, 7-Jun-2006.)

Hypotheses

Ref	Expression
ceqsex2v.1	⊢ A ∈ V
ceqsex2v.2	⊢ B ∈ V
ceqsex2v.3	⊢ (x = A → (φ ↔ ψ))
ceqsex2v.4	⊢ (y = B → (ψ ↔ χ))

Assertion

Ref	Expression
ceqsex2v	⊢ (∃x∃y(x = A ∧ y = B ∧ φ) ↔ χ)

Distinct variable groups:   x,y,A   x,B,y   ψ,x   χ,y Allowed substitution hints:   φ(x,y)   ψ(y)   χ(x)

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Proof of Theorem ceqsex2v

Step	Hyp	Ref	Expression
1		nfv 1619	. 2 ⊢ Ⅎxψ
2		nfv 1619	. 2 ⊢ Ⅎyχ
3		ceqsex2v.1	. 2 ⊢ A ∈ V
4		ceqsex2v.2	. 2 ⊢ B ∈ V
5		ceqsex2v.3	. 2 ⊢ (x = A → (φ ↔ ψ))
6		ceqsex2v.4	. 2 ⊢ (y = B → (ψ ↔ χ))
7	1, 2, 3, 4, 5, 6	ceqsex2 2895	1 ⊢ (∃x∃y(x = A ∧ y = B ∧ φ) ↔ χ)

Colors of variables: wff setvar class

Syntax hints:   → wi 4   ↔ wb 176   ∧ w3a 934  ∃wex 1541   = wceq 1642   ∈ wcel 1710  Vcvv 2859

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-an 360  df-3an 936  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-v 2861

This theorem is referenced by:  ceqsex3v  2897  ceqsex4v  2898  opksnelsik  4265  sikexlem  4295  br1stg  4730  elswap  4740  brswap2  4860  brsnsi  5773  oqelins4  5794  dmpprod  5840  lecex  6115  addccan2nclem1  6263  nmembers1lem1  6268

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