consider P being strict IncSpace-like IncStruct ;
take IT = IncProjStr(# the Points of P,the Lines of P,the Inc of P #); ( IT is with_non-trivial_lines & IT is linear & IT is up-2-rank & IT is strict )
thus
for L being LINE of ex A, B being POINT of st
( A <> B & {A,B} on L )
INCSP_1:def 8 ( IT is linear & IT is up-2-rank & IT is strict )
thus
IT is linear
( IT is up-2-rank & IT is strict )
thus
for A, B being POINT of
for K, L being LINE of st A <> B & {A,B} on K & {A,B} on L holds
K = L
INCSP_1:def 10 IT is strict proof
let A,
B be
POINT of ;
for K, L being LINE of st A <> B & {A,B} on K & {A,B} on L holds
K = Llet K,
L be
LINE of ;
( A <> B & {A,B} on K & {A,B} on L implies K = L )
assume that A3:
A <> B
and A4:
(
{A,B} on K &
{A,B} on L )
;
K = L
reconsider K' =
K,
L' =
L as
LINE of ;
reconsider A' =
A,
B' =
B as
POINT of ;
(
{A',B'} on K' &
{A',B'} on L' )
by A4, Th9;
hence
K = L
by A3, INCSP_1:def 10;
verum
end;
thus
IT is strict
; verum