Theorem cbvrexdva2 2841

Description: Rule used to change the bound variable in a restricted existential quantifier with implicit substitution which also changes the quantifier domain. Deduction form. (Contributed by David Moews, 1-May-2017.)

Hypotheses

Ref	Expression
cbvraldva2.1	⊢ ((φ ∧ x = y) → (ψ ↔ χ))
cbvraldva2.2	⊢ ((φ ∧ x = y) → A = B)

Assertion

Ref	Expression
cbvrexdva2	⊢ (φ → (∃x ∈ A ψ ↔ ∃y ∈ B χ))

Distinct variable groups:   y,A   ψ,y   x,B   χ,x   φ,x,y

Allowed substitution hints:   ψ(x)   χ(y)   A(x)   B(y)

Proof of Theorem cbvrexdva2

Step	Hyp	Ref	Expression
1		simpr 447	. . . . 5 ⊢ ((φ ∧ x = y) → x = y)
2		cbvraldva2.2	. . . . 5 ⊢ ((φ ∧ x = y) → A = B)
3	1, 2	eleq12d 2421	. . . 4 ⊢ ((φ ∧ x = y) → (x ∈ A ↔ y ∈ B))
4		cbvraldva2.1	. . . 4 ⊢ ((φ ∧ x = y) → (ψ ↔ χ))
5	3, 4	anbi12d 691	. . 3 ⊢ ((φ ∧ x = y) → ((x ∈ A ∧ ψ) ↔ (y ∈ B ∧ χ)))
6	5	cbvexdva 2011	. 2 ⊢ (φ → (∃x(x ∈ A ∧ ψ) ↔ ∃y(y ∈ B ∧ χ)))
7		df-rex 2621	. 2 ⊢ (∃x ∈ A ψ ↔ ∃x(x ∈ A ∧ ψ))
8		df-rex 2621	. 2 ⊢ (∃y ∈ B χ ↔ ∃y(y ∈ B ∧ χ))
9	6, 7, 8	3bitr4g 279	1 ⊢ (φ → (∃x ∈ A ψ ↔ ∃y ∈ B χ))

Syntax hints:   → wi 4   ↔ wb 176   ∧ wa 358  ∃wex 1541   = wceq 1642   ∈ wcel 1710  ∃wrex 2616

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 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-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-an 360  df-tru 1319  df-ex 1542  df-nf 1545  df-cleq 2346  df-clel 2349  df-rex 2621

This theorem is referenced by:  cbvrexdva  2843