let A be Euclidean preIfWhileAlgebra; for X being non empty countable set
for s being Element of Funcs (X,INT)
for T being Subset of (Funcs (X,INT))
for f being Euclidean ExecutionFunction of A, Funcs (X,INT),T
for i being Integer
for x being Variable of f holds
( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
let X be non empty countable set ; for s being Element of Funcs (X,INT)
for T being Subset of (Funcs (X,INT))
for f being Euclidean ExecutionFunction of A, Funcs (X,INT),T
for i being Integer
for x being Variable of f holds
( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
let s be Element of Funcs (X,INT); for T being Subset of (Funcs (X,INT))
for f being Euclidean ExecutionFunction of A, Funcs (X,INT),T
for i being Integer
for x being Variable of f holds
( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
let T be Subset of (Funcs (X,INT)); for f being Euclidean ExecutionFunction of A, Funcs (X,INT),T
for i being Integer
for x being Variable of f holds
( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
let f be Euclidean ExecutionFunction of A, Funcs (X,INT),T; for i being Integer
for x being Variable of f holds
( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
let i be Integer; for x being Variable of f holds
( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
let x be Variable of f; ( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
A2:
(. (^ x)) . s = s . ((^ x) . s)
by Def19;
((. x) + i) . s = ((. x) . s) + i
by Def8;
hence
( (f . (s,(x += i))) . x = (s . x) + i & ( for z being Element of X st z <> x holds
(f . (s,(x += i))) . z = s . z ) )
by A2, Th24; verum