let S be non empty 1-sorted ; for T being complete LATTICE
for f, g, h being Function of S,T
for i being Element of S st h = "\/" {f,g},(T |^ the carrier of S) holds
h . i = sup {(f . i),(g . i)}
let T be complete LATTICE; for f, g, h being Function of S,T
for i being Element of S st h = "\/" {f,g},(T |^ the carrier of S) holds
h . i = sup {(f . i),(g . i)}
let f, g, h be Function of S,T; for i being Element of S st h = "\/" {f,g},(T |^ the carrier of S) holds
h . i = sup {(f . i),(g . i)}
let i be Element of S; ( h = "\/" {f,g},(T |^ the carrier of S) implies h . i = sup {(f . i),(g . i)} )
reconsider f9 = f, g9 = g as Element of (T |^ the carrier of S) by Th19;
reconsider SYT = the carrier of S --> T as RelStr-yielding non-Empty ManySortedSet of the carrier of S ;
reconsider SYT = SYT as RelStr-yielding non-Empty reflexive-yielding ManySortedSet of the carrier of S ;
A1:
for i being Element of S holds SYT . i is complete LATTICE
by FUNCOP_1:13;
reconsider f9 = f9, g9 = g9 as Element of (product SYT) by YELLOW_1:def 5;
reconsider DU = {f9,g9} as Subset of (product SYT) ;
assume
h = "\/" {f,g},(T |^ the carrier of S)
; h . i = sup {(f . i),(g . i)}
then h . i =
(sup DU) . i
by YELLOW_1:def 5
.=
"\/" (pi {f,g},i),(SYT . i)
by A1, WAYBEL_3:32
.=
"\/" (pi {f,g},i),T
by FUNCOP_1:13
.=
sup {(f . i),(g . i)}
by CARD_3:26
;
hence
h . i = sup {(f . i),(g . i)}
; verum