let A be non empty set ; for f being monotone UnOp of (BooleLatt A) ex g being V204() Function of (bool A),(bool A) st gfp A,g = gfp f
let f be monotone UnOp of (BooleLatt A); ex g being V204() Function of (bool A),(bool A) st gfp A,g = gfp f
reconsider gf = gfp f as Subset of A by LATTICE3:def 1;
the carrier of (BooleLatt A) = bool A
by LATTICE3:def 1;
then reconsider g = f as V204() Function of (bool A),(bool A) by Th49;
reconsider gg = gfp A,g as Element of (BooleLatt A) by LATTICE3:def 1;
take
g
; gfp A,g = gfp f
gg is_a_fixpoint_of f
by Th7;
then
gg [= gfp f
by Th46;
then A1:
gg c= gf
by LATTICE3:2;
gfp f is_a_fixpoint_of f
by Th45;
then
gf c= gfp A,g
by Th10;
hence
gfp A,g = gfp f
by A1, XBOOLE_0:def 10; verum