let L be Lattice; for u being Element of L
for A being non empty set
for B being Finite_Subset of A
for f being Function of A, the carrier of L st ex x being Element of A st
( x in B & u [= f . x ) holds
u [= FinJoin (B,f)
let u be Element of L; for A being non empty set
for B being Finite_Subset of A
for f being Function of A, the carrier of L st ex x being Element of A st
( x in B & u [= f . x ) holds
u [= FinJoin (B,f)
let A be non empty set ; for B being Finite_Subset of A
for f being Function of A, the carrier of L st ex x being Element of A st
( x in B & u [= f . x ) holds
u [= FinJoin (B,f)
let B be Finite_Subset of A; for f being Function of A, the carrier of L st ex x being Element of A st
( x in B & u [= f . x ) holds
u [= FinJoin (B,f)
let f be Function of A, the carrier of L; ( ex x being Element of A st
( x in B & u [= f . x ) implies u [= FinJoin (B,f) )
given x being Element of A such that A1:
x in B
and
A2:
u [= f . x
; u [= FinJoin (B,f)
f . x [= FinJoin (B,f)
by A1, Th43;
then A3:
(f . x) "\/" (FinJoin (B,f)) = FinJoin (B,f)
by LATTICES:def 3;
then u "\/" (FinJoin (B,f)) =
(u "\/" (f . x)) "\/" (FinJoin (B,f))
by LATTICES:def 5
.=
FinJoin (B,f)
by A2, A3, LATTICES:def 3
;
hence
u [= FinJoin (B,f)
by LATTICES:def 3; verum