Theorem afvvv 41225

Description: If a function's value at an argument is a set, the argument is also a set. (Contributed by Alexander van der Vekens, 25-May-2017.)

Assertion

Ref	Expression
afvvv	⊢ ((𝐹'''𝐴) ∈ 𝐵 → 𝐴 ∈ V)

Proof of Theorem afvvv

Step	Hyp	Ref	Expression
1		afvprc 41224	. . 3 ⊢ (¬ 𝐴 ∈ V → (𝐹'''𝐴) = V)
2		nvelim 41200	. . 3 ⊢ ((𝐹'''𝐴) = V → ¬ (𝐹'''𝐴) ∈ 𝐵)
3	1, 2	syl 17	. 2 ⊢ (¬ 𝐴 ∈ V → ¬ (𝐹'''𝐴) ∈ 𝐵)
4	3	con4i 113	1 ⊢ ((𝐹'''𝐴) ∈ 𝐵 → 𝐴 ∈ V)

Syntax hints:  ¬ wn 3   → wi 4   = wceq 1483   ∈ wcel 1990  Vcvv 3200  '''cafv 41194

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-8 1992  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-rab 2921  df-v 3202  df-un 3579  df-if 4087  df-fv 5896  df-dfat 41196  df-afv 41197

This theorem is referenced by: (None)