let b, a be Int-Location ; :: thesis: for f being FinSeq-Location
for p being preProgram of SCM+FSA st ( b := f,a in rng p or f,a := b in rng p ) holds
First*NotUsed p <> f
let f be FinSeq-Location ; :: thesis: for p being preProgram of SCM+FSA st ( b := f,a in rng p or f,a := b in rng p ) holds
First*NotUsed p <> f
let p be preProgram of SCM+FSA ; :: thesis: ( ( b := f,a in rng p or f,a := b in rng p ) implies First*NotUsed p <> f )
assume ( b := f,a in rng p or f,a := b in rng p ) ; :: thesis: First*NotUsed p <> f
then consider i being Instruction of SCM+FSA such that
A1: i in rng p and
A2: ( i = b := f,a or i = f,a := b ) ;
UsedInt*Loc i = {f} by A2, Th37;
then A3: {f} c= UsedInt*Loc p by A1, Th39;
not First*NotUsed p in UsedInt*Loc p by Th61;
hence First*NotUsed p <> f by A3, ZFMISC_1:37; :: thesis: verum