let I be non empty set ; for J being non-Empty TopStruct-yielding ManySortedSet of I
for i1, i2 being Element of I
for xi1 being Element of (J . i1)
for Ai2 being Subset of (J . i2)
for f being Element of (product J) st i1 <> i2 holds
( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 )
let J be non-Empty TopStruct-yielding ManySortedSet of I; for i1, i2 being Element of I
for xi1 being Element of (J . i1)
for Ai2 being Subset of (J . i2)
for f being Element of (product J) st i1 <> i2 holds
( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 )
let i1, i2 be Element of I; for xi1 being Element of (J . i1)
for Ai2 being Subset of (J . i2)
for f being Element of (product J) st i1 <> i2 holds
( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 )
let xi1 be Element of (J . i1); for Ai2 being Subset of (J . i2)
for f being Element of (product J) st i1 <> i2 holds
( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 )
let Ai2 be Subset of (J . i2); for f being Element of (product J) st i1 <> i2 holds
( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 )
let f be Element of (product J); ( i1 <> i2 implies ( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 ) )
reconsider Ai29 = Ai2 as Subset of ((Carrier J) . i2) by YELLOW_6:2;
xi1 in the carrier of (J . i1)
;
then A1:
xi1 in (Carrier J) . i1
by YELLOW_6:2;
f in the carrier of (product J)
;
then A2:
f in product (Carrier J)
by WAYBEL18:def 3;
assume
i1 <> i2
; ( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 )
then
( f in (proj ((Carrier J),i2)) " Ai29 iff f +* (i1,xi1) in (proj ((Carrier J),i2)) " Ai29 )
by A1, A2, Th6;
hence
( f in (proj (J,i2)) " Ai2 iff f +* (i1,xi1) in (proj (J,i2)) " Ai2 )
by WAYBEL18:def 4; verum