ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  hbs1f Structured version   Unicode version

Theorem hbs1f 1661
Description: If is not free in , it is not free in . (Contributed by NM, 5-Aug-1993.) (Proof shortened by Andrew Salmon, 25-May-2011.)
Hypothesis
Ref Expression
hbs1f.1
Assertion
Ref Expression
hbs1f

Proof of Theorem hbs1f
StepHypRef Expression
1 hbs1f.1 . . 3
21sbh 1656 . 2
32, 1hbxfrbi 1358 1
Colors of variables: wff set class
Syntax hints:   wi 4  wal 1240  wsb 1642
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-5 1333  ax-gen 1335  ax-ie1 1379  ax-ie2 1380  ax-4 1397  ax-i9 1420  ax-ial 1424
This theorem depends on definitions:  df-bi 110  df-sb 1643
This theorem is referenced by: (None)
  Copyright terms: Public domain W3C validator