let L1, L2 be non empty Poset; :: thesis: ( L1,L2 are_isomorphic & L1 is complete & L1 is satisfying_axiom_K implies L2 is satisfying_axiom_K )
assume that
A1:
L1,L2 are_isomorphic
and
A2:
( L1 is complete & L1 is satisfying_axiom_K )
; :: thesis: L2 is satisfying_axiom_K
consider f being Function of L1,L2 such that
A3:
f is isomorphic
by A1, WAYBEL_1:def 8;
A4:
f is one-to-one
by A3;
reconsider g = f " as Function of L2,L1 by A3, WAYBEL_0:67;
now let x be
Element of
L2;
:: thesis: x = sup (compactbelow x)
f is
sups-preserving
by A3;
then A5:
f preserves_sup_of compactbelow (g . x)
by WAYBEL_0:def 33;
A6:
ex_sup_of compactbelow (g . x),
L1
by A2, YELLOW_0:17;
A7:
L1 is non
empty complete Poset
by A2;
then A8:
L2 is non
empty up-complete Poset
by A1, Th30;
( not the
carrier of
L1 is
empty &
x in the
carrier of
L2 )
;
then
x in dom g
by FUNCT_2:def 1;
then A9:
x in rng f
by A4, FUNCT_1:55;
hence x =
f . (g . x)
by A4, FUNCT_1:57
.=
f . (sup (compactbelow (g . x)))
by A2, WAYBEL_8:def 3
.=
sup (f .: (compactbelow (g . x)))
by A5, A6, WAYBEL_0:def 31
.=
sup (compactbelow (f . (g . x)))
by A3, A7, A8, Th29
.=
sup (compactbelow x)
by A4, A9, FUNCT_1:57
;
:: thesis: verum end;
hence
L2 is satisfying_axiom_K
by WAYBEL_8:def 3; :: thesis: verum