consider h2, h1 being morphism of (OrdC 3) such that
A2:
( not h2 is identity & not h1 is identity & cod h2 = dom h1 )
and
A3:
Ob (OrdC 3) = {(dom h2),(cod h2),(cod h1)}
and
A4:
Mor (OrdC 3) = {(dom h2),(cod h2),(cod h1),h2,h1,(h1 (*) h2)}
and
A5:
dom h2, cod h2, cod h1,h2,h1,h1 (*) h2 are_mutually_distinct
by Th18;
A6:
h1 |> h2
by A2, CAT_7:5;
A7:
ex F being covariant Functor of (OrdC 3),C st
for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( F . g1 = f1 & F . g2 = f2 )
proof
defpred S1[
object ,
object ]
means ( ( $1
= dom h2 implies $2
= dom f2 ) & ( $1
= cod h2 implies $2
= cod f2 ) & ( $1
= cod h1 implies $2
= cod f1 ) & ( $1
= h2 implies $2
= f2 ) & ( $1
= h1 implies $2
= f1 ) & ( $1
= h1 (*) h2 implies $2
= f1 (*) f2 ) );
A8:
for
x being
object st
x in the
carrier of
(OrdC 3) holds
ex
y being
object st
(
y in the
carrier of
C &
S1[
x,
y] )
consider F being
Function of the
carrier of
(OrdC 3), the
carrier of
C such that A16:
for
x being
object st
x in the
carrier of
(OrdC 3) holds
S1[
x,
F . x]
from FUNCT_2:sch 1(A8);
reconsider F =
F as
Functor of
(OrdC 3),
C ;
for
g being
morphism of
(OrdC 3) st
g is
identity holds
F . g is
identity
then A20:
F is
identity-preserving
by CAT_6:def 22;
A21:
for
g being
morphism of
(OrdC 3) st
g = h2 holds
F . g = f2
A24:
for
g being
morphism of
(OrdC 3) st
g = h1 holds
F . g = f1
for
g1,
g2 being
morphism of
(OrdC 3) st
g1 |> g2 holds
(
F . g1 |> F . g2 &
F . (g1 (*) g2) = (F . g1) (*) (F . g2) )
then reconsider F =
F as
covariant Functor of
(OrdC 3),
C by A20, CAT_6:def 23, CAT_6:def 25;
take
F
;
for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( F . g1 = f1 & F . g2 = f2 )
let g1,
g2 be
morphism of
(OrdC 3);
( g1 |> g2 & not g1 is identity & not g2 is identity implies ( F . g1 = f1 & F . g2 = f2 ) )
assume A93:
g1 |> g2
;
( g1 is identity or g2 is identity or ( F . g1 = f1 & F . g2 = f2 ) )
assume A94:
( not
g1 is
identity & not
g2 is
identity )
;
( F . g1 = f1 & F . g2 = f2 )
A95:
(
g1 = dom h2 or
g1 = cod h2 or
g1 = cod h1 or
g1 = h2 or
g1 = h1 or
g1 = h1 (*) h2 )
by A4, ENUMSET1:def 4;
A96:
(
g2 = dom h2 or
g2 = cod h2 or
g2 = cod h1 or
g2 = h2 or
g2 = h1 or
g2 = h1 (*) h2 )
by A4, ENUMSET1:def 4;
A97:
(
g1 = h1 &
g2 = h2 )
proof
assume A98:
(
g1 <> h1 or
g2 <> h2 )
;
contradiction
end;
thus
(
F . g1 = f1 &
F . g2 = f2 )
by A21, A24, A97;
verum
end;
A113:
for F1, F2 being covariant Functor of (OrdC 3),C st ( for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( F1 . g1 = f1 & F1 . g2 = f2 ) ) & ( for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( F2 . g1 = f1 & F2 . g2 = f2 ) ) holds
F1 = F2
proof
let F1,
F2 be
covariant Functor of
(OrdC 3),
C;
( ( for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( F1 . g1 = f1 & F1 . g2 = f2 ) ) & ( for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( F2 . g1 = f1 & F2 . g2 = f2 ) ) implies F1 = F2 )
assume A114:
for
g1,
g2 being
morphism of
(OrdC 3) st
g1 |> g2 & not
g1 is
identity & not
g2 is
identity holds
(
F1 . g1 = f1 &
F1 . g2 = f2 )
;
( ex g1, g2 being morphism of (OrdC 3) st
( g1 |> g2 & not g1 is identity & not g2 is identity & not ( F2 . g1 = f1 & F2 . g2 = f2 ) ) or F1 = F2 )
assume A115:
for
g1,
g2 being
morphism of
(OrdC 3) st
g1 |> g2 & not
g1 is
identity & not
g2 is
identity holds
(
F2 . g1 = f1 &
F2 . g2 = f2 )
;
F1 = F2
for
x being
object st
x in the
carrier of
(OrdC 3) holds
F1 . x = F2 . x
proof
let x be
object ;
( x in the carrier of (OrdC 3) implies F1 . x = F2 . x )
assume
x in the
carrier of
(OrdC 3)
;
F1 . x = F2 . x
then A116:
x in {(dom h2),(cod h2),(cod h1),h2,h1,(h1 (*) h2)}
by A4, CAT_6:def 1;
A117:
F1 . h1 =
f1
by A2, A6, A114
.=
F2 . h1
by A2, A6, A115
;
A118:
F1 . h2 =
f2
by A2, A6, A114
.=
F2 . h2
by A2, A6, A115
;
A119:
(
F1 is
multiplicative &
F2 is
multiplicative )
by CAT_6:def 25;
end;
hence
F1 = F2
by FUNCT_2:12;
verum
end;
thus
( ex b1 being covariant Functor of (OrdC 3),C st
for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( b1 . g1 = f1 & b1 . g2 = f2 ) & ( for b1, b2 being covariant Functor of (OrdC 3),C st ( for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( b1 . g1 = f1 & b1 . g2 = f2 ) ) & ( for g1, g2 being morphism of (OrdC 3) st g1 |> g2 & not g1 is identity & not g2 is identity holds
( b2 . g1 = f1 & b2 . g2 = f2 ) ) holds
b1 = b2 ) )
by A7, A113; verum