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Theorem nf5d 2258
 Description: Deduce that 𝑥 is not free in 𝜓 in a context. (Contributed by Mario Carneiro, 24-Sep-2016.)
Hypotheses
Ref Expression
nf5d.1 𝑥𝜑
nf5d.2 (𝜑 → (𝜓 → ∀𝑥𝜓))
Assertion
Ref Expression
nf5d (𝜑 → Ⅎ𝑥𝜓)

Proof of Theorem nf5d
StepHypRef Expression
1 nf5d.1 . . 3 𝑥𝜑
2 nf5d.2 . . 3 (𝜑 → (𝜓 → ∀𝑥𝜓))
31, 2alrimi 2178 . 2 (𝜑 → ∀𝑥(𝜓 → ∀𝑥𝜓))
4 nf5-1 2116 . 2 (∀𝑥(𝜓 → ∀𝑥𝜓) → Ⅎ𝑥𝜓)
53, 4syl 17 1 (𝜑 → Ⅎ𝑥𝜓)
 Colors of variables: wff setvar class Syntax hints:   → wi 4  ∀wal 1520  Ⅎwnf 1765 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1777  ax-4 1791  ax-5 1888  ax-6 1947  ax-7 1992  ax-10 2112  ax-12 2141 This theorem depends on definitions:  df-bi 208  df-ex 1762  df-nf 1766 This theorem is referenced by:  dvelimhw  2322  nfeqf  2354  cbv1h  2381  axc16nfALT  2416  nfsb2  2476  nfsb2ALT  2554  distel  32657  bj-cbv1hv  33663  wl-ax11-lem3  34350
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