Theorem rmobiia 2802

Description: Formula-building rule for restricted existential quantifier (inference rule). (Contributed by NM, 16-Jun-2017.)

Hypothesis

Ref	Expression
rmobiia.1	⊢ (x ∈ A → (φ ↔ ψ))

Assertion

Ref	Expression
rmobiia	⊢ (∃*x ∈ A φ ↔ ∃*x ∈ A ψ)

Proof of Theorem rmobiia

Step	Hyp	Ref	Expression
1		rmobiia.1	. . . 4 ⊢ (x ∈ A → (φ ↔ ψ))
2	1	pm5.32i 618	. . 3 ⊢ ((x ∈ A ∧ φ) ↔ (x ∈ A ∧ ψ))
3	2	mobii 2240	. 2 ⊢ (∃*x(x ∈ A ∧ φ) ↔ ∃*x(x ∈ A ∧ ψ))
4		df-rmo 2623	. 2 ⊢ (∃*x ∈ A φ ↔ ∃*x(x ∈ A ∧ φ))
5		df-rmo 2623	. 2 ⊢ (∃*x ∈ A ψ ↔ ∃*x(x ∈ A ∧ ψ))
6	3, 4, 5	3bitr4i 268	1 ⊢ (∃*x ∈ A φ ↔ ∃*x ∈ A ψ)

This proof depends on syntax axioms:   → wi 4   ↔ wb 176   ∧ wa 358   ∈ wcel 1710  ∃*wmo 2205  ∃*wrmo 2618

This proof depends on 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-11 1746

This proof depends on definitions:  df-bi 177  df-an 360  df-tru 1319  df-ex 1542  df-nf 1545  df-eu 2208  df-mo 2209  df-rmo 2623

This theorem is used by:  rmobii  2803