let A be Euclidean preIfWhileAlgebra; :: thesis: for X being non empty countable set
for s being Element of Funcs X,INT
for b being Element of X
for g being Euclidean ExecutionFunction of A, Funcs X,INT ,(Funcs X,INT ) \ b,0
for t being INT-Expression of A,g holds
( (g . s,(t is_odd )) . b = (t . s) mod 2 & (g . s,(t is_even )) . b = ((t . s) + 1) mod 2 & ( for z being Element of X st z <> b holds
( (g . s,(t is_odd )) . z = s . z & (g . s,(t is_even )) . z = s . z ) ) )
let X be non empty countable set ; :: thesis: for s being Element of Funcs X,INT
for b being Element of X
for g being Euclidean ExecutionFunction of A, Funcs X,INT ,(Funcs X,INT ) \ b,0
for t being INT-Expression of A,g holds
( (g . s,(t is_odd )) . b = (t . s) mod 2 & (g . s,(t is_even )) . b = ((t . s) + 1) mod 2 & ( for z being Element of X st z <> b holds
( (g . s,(t is_odd )) . z = s . z & (g . s,(t is_even )) . z = s . z ) ) )
let s be Element of Funcs X,INT ; :: thesis: for b being Element of X
for g being Euclidean ExecutionFunction of A, Funcs X,INT ,(Funcs X,INT ) \ b,0
for t being INT-Expression of A,g holds
( (g . s,(t is_odd )) . b = (t . s) mod 2 & (g . s,(t is_even )) . b = ((t . s) + 1) mod 2 & ( for z being Element of X st z <> b holds
( (g . s,(t is_odd )) . z = s . z & (g . s,(t is_even )) . z = s . z ) ) )
let b be Element of X; :: thesis: for g being Euclidean ExecutionFunction of A, Funcs X,INT ,(Funcs X,INT ) \ b,0
for t being INT-Expression of A,g holds
( (g . s,(t is_odd )) . b = (t . s) mod 2 & (g . s,(t is_even )) . b = ((t . s) + 1) mod 2 & ( for z being Element of X st z <> b holds
( (g . s,(t is_odd )) . z = s . z & (g . s,(t is_even )) . z = s . z ) ) )
let f be Euclidean ExecutionFunction of A, Funcs X,INT ,(Funcs X,INT ) \ b,0 ; :: thesis: for t being INT-Expression of A,f holds
( (f . s,(t is_odd )) . b = (t . s) mod 2 & (f . s,(t is_even )) . b = ((t . s) + 1) mod 2 & ( for z being Element of X st z <> b holds
( (f . s,(t is_odd )) . z = s . z & (f . s,(t is_even )) . z = s . z ) ) )
reconsider y = b as Variable of f by ELEM;
let t be INT-Expression of A,f; :: thesis: ( (f . s,(t is_odd )) . b = (t . s) mod 2 & (f . s,(t is_even )) . b = ((t . s) + 1) mod 2 & ( for z being Element of X st z <> b holds
( (f . s,(t is_odd )) . z = s . z & (f . s,(t is_even )) . z = s . z ) ) )
( (. 2,A,f) . s = 2 & dom (t + 1) = Funcs X,INT ) by FUNCOP_1:13, FUNCT_2:def 1;
then ( t is_odd = y := (t mod (. 2,A,f)) & (t mod (. 2,A,f)) . s = (t . s) mod 2 & t is_even = y := ((t + 1) mod (. 2,A,f)) & (t + 1) . s = 1 + (t . s) & ((t + 1) mod (. 2,A,f)) . s = ((t + 1) . s) mod 2 ) by DEFmod2, VALUED_1:def 2;
hence ( (f . s,(t is_odd )) . b = (t . s) mod 2 & (f . s,(t is_even )) . b = ((t . s) + 1) mod 2 & ( for z being Element of X st z <> b holds
( (f . s,(t is_odd )) . z = s . z & (f . s,(t is_even )) . z = s . z ) ) ) by Th111; :: thesis: verum