let L be complete LATTICE; for F being proper Filter of (BoolePoset ([#] L)) holds a_net F in NetUniv L
let F be proper Filter of (BoolePoset ([#] L)); a_net F in NetUniv L
set S = { [a,f] where a is Element of L, f is Element of F : a in f } ;
set UN = the_universe_of the carrier of L;
reconsider UN = the_universe_of the carrier of L as universal set ;
the_transitive-closure_of the carrier of L in UN
by CLASSES1:2;
then A1:
the carrier of L in UN
by CLASSES1:3, CLASSES1:52;
then
bool the carrier of L in UN
by CLASSES2:59;
then A2:
[: the carrier of L,(bool the carrier of L):] in UN
by A1, CLASSES2:61;
{ [a,f] where a is Element of L, f is Element of F : a in f } c= [: the carrier of L,(bool the carrier of L):]
by Lm4;
then
( { [a,f] where a is Element of L, f is Element of F : a in f } = the carrier of (a_net F) & { [a,f] where a is Element of L, f is Element of F : a in f } in UN )
by A2, CLASSES1:def 1, YELLOW19:def 4;
hence
a_net F in NetUniv L
by YELLOW_6:def 11; verum