let D, D', E be non empty set ; for d' being Element of D'
for F being Function of [:D,D':],E holds F [:] (<*> D),d' = <*> E
let d' be Element of D'; for F being Function of [:D,D':],E holds F [:] (<*> D),d' = <*> E
let F be Function of [:D,D':],E; F [:] (<*> D),d' = <*> E
reconsider r = F [:] (<*> D),d' as FinSequence of E by Th97;
len (<*> D) = 0
;
then
len r = 0
by Th98;
hence
F [:] (<*> D),d' = <*> E
; verum