Theorem bj-exexbiex 37435

Description: Adding a second quantifier over the same variable is a transparent operation, (∃∃ case). (Contributed by BJ, 20-Oct-2019.)

Assertion

Ref	Expression
bj-exexbiex	⊢ (∃𝑥∃𝑥𝜑 ↔ ∃𝑥𝜑)

Proof of Theorem bj-exexbiex

Step	Hyp	Ref	Expression
1		nfe1 2187	. 2 ⊢ Ⅎ𝑥∃𝑥𝜑
2	1	19.9 2243	1 ⊢ (∃𝑥∃𝑥𝜑 ↔ ∃𝑥𝜑)

This proof depends on syntax axioms:   ↔ wb 209  ∃wex 1812

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-10 2178  ax-12 2215

This proof depends on definitions:  df-bi 210  df-ex 1813  df-nf 1817

This theorem is used by: (None)