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 I being Element of A holds S is_invariant_wrt I,f
let S be non empty set ; for T being Subset of S
for f being ExecutionFunction of A,S,T
for I being Element of A holds S is_invariant_wrt I,f
let T be Subset of S; for f being ExecutionFunction of A,S,T
for I being Element of A holds S is_invariant_wrt I,f
let f be ExecutionFunction of A,S,T; for I being Element of A holds S is_invariant_wrt I,f
let I be Element of A; S is_invariant_wrt I,f
let s be Element of S; AOFA_000:def 39 ( s in S implies f . (s,I) in S )
thus
( s in S implies f . (s,I) in S )
; verum