A2:
[#] ((TOP-REAL 0) | ([#] (TOP-REAL 0))) = {(0. (TOP-REAL 0))}
by EUCLID:25, JORDAN2C:113, A1;
let M be non empty TopSpace; ( M is discrete implies M is 0 -locally_euclidean )
assume A16:
M is discrete
; M is 0 -locally_euclidean
for p being Point of M ex U being a_neighborhood of p st U, [#] (TOP-REAL 0) are_homeomorphic
proof
let p be
Point of
M;
ex U being a_neighborhood of p st U, [#] (TOP-REAL 0) are_homeomorphic
reconsider U =
{p} as
Subset of
M by ZFMISC_1:37;
A17:
(
U is
open &
p in U )
by A16, TDLAT_3:17, TARSKI:def 1;
then reconsider U =
U as
a_neighborhood of
p by CONNSP_2:5;
take
U
;
U, [#] (TOP-REAL 0) are_homeomorphic
set f =
{[p,(0. (TOP-REAL 0))]};
A18:
p in [#] (M | U)
by A17, PRE_TOPC:def 10;
A19:
[p,(0. (TOP-REAL 0))] in [: the carrier of (M | U), the carrier of ((TOP-REAL 0) | ([#] (TOP-REAL 0))):]
by A18, ZFMISC_1:106, A1;
A20:
dom {[p,(0. (TOP-REAL 0))]} = U
by RELAT_1:23;
then A21:
dom {[p,(0. (TOP-REAL 0))]} = [#] (M | U)
by PRE_TOPC:def 10;
then reconsider f =
{[p,(0. (TOP-REAL 0))]} as
Function of
(M | U),
((TOP-REAL 0) | ([#] (TOP-REAL 0))) by A19, FUNCT_2:def 1, ZFMISC_1:37;
A22:
rng f = [#] ((TOP-REAL 0) | ([#] (TOP-REAL 0)))
by A2, RELAT_1:23;
for
P being
Subset of
(M | U) holds
(
P is
closed iff
f .: P is
closed )
then
f is
being_homeomorphism
by A21, A22, TOPS_2:72;
then
M | U,
(TOP-REAL 0) | ([#] (TOP-REAL 0)) are_homeomorphic
by T_0TOPSP:def 1;
hence
U,
[#] (TOP-REAL 0) are_homeomorphic
by METRIZTS:def 1;
verum
end;
hence
M is 0 -locally_euclidean
by Th15; verum