let X1, X2 be non empty set ; for cF1 being Filter of X1
for cF2 being Filter of X2
for Y being non empty Hausdorff regular TopSpace
for f being Function of [:X1,X2:],Y st lim_filter (f,<.cF1,cF2.)) <> {} & ( for x being Element of X1 holds lim_filter ((ProjMap1 (f,x)),cF2) <> {} ) holds
lim_filter (f,<.cF1,cF2.)) = lim_filter ((lim_in_cod2 (f,cF2)),cF1)
let cF1 be Filter of X1; for cF2 being Filter of X2
for Y being non empty Hausdorff regular TopSpace
for f being Function of [:X1,X2:],Y st lim_filter (f,<.cF1,cF2.)) <> {} & ( for x being Element of X1 holds lim_filter ((ProjMap1 (f,x)),cF2) <> {} ) holds
lim_filter (f,<.cF1,cF2.)) = lim_filter ((lim_in_cod2 (f,cF2)),cF1)
let cF2 be Filter of X2; for Y being non empty Hausdorff regular TopSpace
for f being Function of [:X1,X2:],Y st lim_filter (f,<.cF1,cF2.)) <> {} & ( for x being Element of X1 holds lim_filter ((ProjMap1 (f,x)),cF2) <> {} ) holds
lim_filter (f,<.cF1,cF2.)) = lim_filter ((lim_in_cod2 (f,cF2)),cF1)
let Y be non empty Hausdorff regular TopSpace; for f being Function of [:X1,X2:],Y st lim_filter (f,<.cF1,cF2.)) <> {} & ( for x being Element of X1 holds lim_filter ((ProjMap1 (f,x)),cF2) <> {} ) holds
lim_filter (f,<.cF1,cF2.)) = lim_filter ((lim_in_cod2 (f,cF2)),cF1)
let f be Function of [:X1,X2:],Y; ( lim_filter (f,<.cF1,cF2.)) <> {} & ( for x being Element of X1 holds lim_filter ((ProjMap1 (f,x)),cF2) <> {} ) implies lim_filter (f,<.cF1,cF2.)) = lim_filter ((lim_in_cod2 (f,cF2)),cF1) )
assume that
A1:
lim_filter (f,<.cF1,cF2.)) <> {}
and
A2:
for x being Element of X1 holds lim_filter ((ProjMap1 (f,x)),cF2) <> {}
; lim_filter (f,<.cF1,cF2.)) = lim_filter ((lim_in_cod2 (f,cF2)),cF1)
consider y being object such that
A3:
lim_filter (f,<.cF1,cF2.)) = {y}
by A1, ZFMISC_1:131;
A4:
y in lim_filter (f,<.cF1,cF2.))
by A3, TARSKI:def 1;
A5:
lim_filter (f,<.cF1,cF2.)) c= lim_filter ((lim_in_cod2 (f,cF2)),cF1)
by A2, Th79;
( not lim_filter ((lim_in_cod2 (f,cF2)),cF1) is empty & lim_filter ((lim_in_cod2 (f,cF2)),cF1) is trivial )
by A3, A5;
then
ex z being object st lim_filter ((lim_in_cod2 (f,cF2)),cF1) = {z}
by ZFMISC_1:131;
hence
lim_filter (f,<.cF1,cF2.)) = lim_filter ((lim_in_cod2 (f,cF2)),cF1)
by A3, A5, A4, TARSKI:def 1; verum