Theorem euimmo 2660

Description: Uniqueness implies "at most one" through reverse implication. (Contributed by NM, 22-Apr-1995.)

Assertion

Ref	Expression
euimmo	⊢ (∀𝑥(𝜑 → 𝜓) → (∃!𝑥𝜓 → ∃*𝑥𝜑))

Proof of Theorem euimmo

Step	Hyp	Ref	Expression
1		eumo 2636	. 2 ⊢ (∃!𝑥𝜓 → ∃*𝑥𝜓)
2		moim 2657	. 2 ⊢ (∀𝑥(𝜑 → 𝜓) → (∃*𝑥𝜓 → ∃*𝑥𝜑))
3	1, 2	syl5 34	1 ⊢ (∀𝑥(𝜑 → 𝜓) → (∃!𝑥𝜓 → ∃*𝑥𝜑))

Syntax hints:   → wi 4  ∀wal 1630  ∃!weu 2607  ∃*wmo 2608

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1871  ax-4 1886  ax-5 1988  ax-6 2054  ax-7 2090  ax-10 2168  ax-12 2196

This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-ex 1854  df-nf 1859  df-eu 2611  df-mo 2612

This theorem is referenced by:  euim  2661  2eumo  2683  moeq3  3524  reuss2  4050