let A be preIfWhileAlgebra; for S being non empty set
for T being Subset of S
for f being ExecutionFunction of A,S,T
for C, I, J being Element of A st C is_terminating_wrt f & I is_terminating_wrt f & J is_terminating_wrt f holds
if-then-else C,I,J is_terminating_wrt f
let S be non empty set ; for T being Subset of S
for f being ExecutionFunction of A,S,T
for C, I, J being Element of A st C is_terminating_wrt f & I is_terminating_wrt f & J is_terminating_wrt f holds
if-then-else C,I,J is_terminating_wrt f
let T be Subset of S; for f being ExecutionFunction of A,S,T
for C, I, J being Element of A st C is_terminating_wrt f & I is_terminating_wrt f & J is_terminating_wrt f holds
if-then-else C,I,J is_terminating_wrt f
let f be ExecutionFunction of A,S,T; for C, I, J being Element of A st C is_terminating_wrt f & I is_terminating_wrt f & J is_terminating_wrt f holds
if-then-else C,I,J is_terminating_wrt f
let C, I, J be Element of A; ( C is_terminating_wrt f & I is_terminating_wrt f & J is_terminating_wrt f implies if-then-else C,I,J is_terminating_wrt f )
assume that
A1:
for s being Element of S holds [s,C] in TerminatingPrograms A,S,T,f
and
A2:
for s being Element of S holds [s,I] in TerminatingPrograms A,S,T,f
and
A3:
for s being Element of S holds [s,J] in TerminatingPrograms A,S,T,f
; AOFA_000:def 37 if-then-else C,I,J is_terminating_wrt f
let s be Element of S; AOFA_000:def 37 [s,(if-then-else C,I,J)] in TerminatingPrograms A,S,T,f
A4:
( f . s,C in T or f . s,C nin T )
;
A5:
[s,C] in TerminatingPrograms A,S,T,f
by A1;
A6:
[(f . s,C),I] in TerminatingPrograms A,S,T,f
by A2;
[(f . s,C),J] in TerminatingPrograms A,S,T,f
by A3;
hence
[s,(if-then-else C,I,J)] in TerminatingPrograms A,S,T,f
by A4, A5, A6, Def35; verum