let I be non empty set ; for J being RelStr-yielding non-Empty reflexive-yielding ManySortedSet of I st ( for i being Element of I holds J . i is complete LATTICE ) holds
for X being Subset of (product J)
for i being Element of I holds (sup X) . i = sup (pi (X,i))
let J be RelStr-yielding non-Empty reflexive-yielding ManySortedSet of I; ( ( for i being Element of I holds J . i is complete LATTICE ) implies for X being Subset of (product J)
for i being Element of I holds (sup X) . i = sup (pi (X,i)) )
assume A1:
for i being Element of I holds J . i is complete LATTICE
; for X being Subset of (product J)
for i being Element of I holds (sup X) . i = sup (pi (X,i))
then reconsider L = product J as complete LATTICE by Th31;
A2:
L is complete
;
let X be Subset of (product J); for i being Element of I holds (sup X) . i = sup (pi (X,i))
let i be Element of I; (sup X) . i = sup (pi (X,i))
A3:
sup X is_>=_than X
by A2, YELLOW_0:32;
A4:
(sup X) . i is_>=_than pi (X,i)
A7:
J . i is complete LATTICE
by A1;
hence
(sup X) . i = sup (pi (X,i))
by A4, A7, YELLOW_0:32; verum