let F be Field; :: thesis: for p being linear Element of the carrier of (Polynom-Ring F) holds
( (Polynom-Ring F) / ({p} -Ideal),F are_isomorphic & the carrier of (embField (emb p)) = the carrier of F )

let p be linear Element of the carrier of (Polynom-Ring F); :: thesis: ( (Polynom-Ring F) / ({p} -Ideal),F are_isomorphic & the carrier of (embField (emb p)) = the carrier of F )
set FP = (Polynom-Ring F) / ({p} -Ideal);
set I = {p} -Ideal ;
set f = emb p;
set FX = Polynom-Ring F;
A: (Polynom-Ring F) / ({p} -Ideal), Polynom-Ring p are_isomorphic by RING_4:48;
Polynom-Ring p,F are_isomorphic by polyd;
hence (Polynom-Ring F) / ({p} -Ideal),F are_isomorphic by A, RING_3:44; :: thesis: the carrier of (embField (emb p)) = the carrier of F
B: now :: thesis: for q being Element of the carrier of (Polynom-Ring F) ex r being constant Element of the carrier of (Polynom-Ring F) st Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),q) = Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),r)
let q be Element of the carrier of (Polynom-Ring F); :: thesis: ex r being constant Element of the carrier of (Polynom-Ring F) st Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),q) = Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),r)
B1: q = ((q div p) *' p) + (q mod p) by RING_4:4;
reconsider r = q mod p, d = q div p as Element of the carrier of (Polynom-Ring F) by POLYNOM3:def 10;
deg r < deg p by divmod;
then deg r < 1 by defl;
then (deg r) + 1 <= 1 by INT_1:7;
then ((deg r) + 1) - 1 <= 1 - 1 by XREAL_1:9;
then reconsider r = r as constant Element of the carrier of (Polynom-Ring F) by RING_4:def 4;
(q div p) *' p = d * p by POLYNOM3:def 10;
then q = (d * p) + r by B1, POLYNOM3:def 10;
then B2: q - r = (d * p) + (r - r) by RLVECT_1:28
.= (d * p) + (0. (Polynom-Ring F)) by RLVECT_1:15 ;
{p} -Ideal = { (p * c) where c is Element of (Polynom-Ring F) : verum } by IDEAL_1:64;
then p * d in {p} -Ideal ;
then d * p in {p} -Ideal by GROUP_1:def 12;
then Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),q) = Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),r) by B2, RING_1:6;
hence ex r being constant Element of the carrier of (Polynom-Ring F) st Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),q) = Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),r) ; :: thesis: verum
end;
E: now :: thesis: for o being object st o in the carrier of ((Polynom-Ring F) / ({p} -Ideal)) holds
o in rng (emb p)
let o be object ; :: thesis: ( o in the carrier of ((Polynom-Ring F) / ({p} -Ideal)) implies o in rng (emb p) )
assume o in the carrier of ((Polynom-Ring F) / ({p} -Ideal)) ; :: thesis: o in rng (emb p)
then consider q being Element of the carrier of (Polynom-Ring F) such that
E1: o = Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),q) by RING_1:11;
consider r being constant Element of the carrier of (Polynom-Ring F) such that
E2: Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),q) = Class ((EqRel ((Polynom-Ring F),({p} -Ideal))),r) by B;
consider a being Element of F such that
E3: a | F = r by RING_4:20;
E4: (emb p) . a = o by E1, E2, E3, FIELD_1:39;
dom (emb p) = the carrier of F by FUNCT_2:def 1;
hence o in rng (emb p) by E4, FUNCT_1:def 3; :: thesis: verum
end;
now :: thesis: for o being object st o in rng (emb p) holds
o in the carrier of ((Polynom-Ring F) / ({p} -Ideal))
let o be object ; :: thesis: ( o in rng (emb p) implies o in the carrier of ((Polynom-Ring F) / ({p} -Ideal)) )
assume B: o in rng (emb p) ; :: thesis: o in the carrier of ((Polynom-Ring F) / ({p} -Ideal))
rng (emb p) c= the carrier of ((Polynom-Ring F) / ({p} -Ideal)) by RELAT_1:def 19;
hence o in the carrier of ((Polynom-Ring F) / ({p} -Ideal)) by B; :: thesis: verum
end;
then C: rng (emb p) = the carrier of ((Polynom-Ring F) / ({p} -Ideal)) by E, TARSKI:2;
X: ( [#] F = the carrier of F & [#] ((Polynom-Ring F) / ({p} -Ideal)) = the carrier of ((Polynom-Ring F) / ({p} -Ideal)) ) ;
thus the carrier of (embField (emb p)) = carr (emb p) by FIELD_2:def 7
.= ( the carrier of ((Polynom-Ring F) / ({p} -Ideal)) \ (rng (emb p))) \/ the carrier of F by X, FIELD_2:def 2
.= {} \/ the carrier of F by C, XBOOLE_1:37
.= the carrier of F ; :: thesis: verum