let K be Field; for p, q being FinSequence of K st p is first-symmetry-of-circulant & q is first-symmetry-of-circulant & len p = len q holds
p + q is first-symmetry-of-circulant
let p, q be FinSequence of K; ( p is first-symmetry-of-circulant & q is first-symmetry-of-circulant & len p = len q implies p + q is first-symmetry-of-circulant )
set n = len p;
assume that
A1:
p is first-symmetry-of-circulant
and
A2:
q is first-symmetry-of-circulant
and
A3:
len p = len q
; p + q is first-symmetry-of-circulant
consider M2 being Matrix of len p,K such that
A4:
M2 is_symmetry_circulant_about q
by A2, A3;
A5:
dom p = Seg (len p)
by FINSEQ_1:def 3;
dom q = Seg (len p)
by A3, FINSEQ_1:def 3;
then
dom (p + q) = dom p
by A5, POLYNOM1:1;
then A6:
len (p + q) = len p
by A5, FINSEQ_1:def 3;
consider M1 being Matrix of len p,K such that
A7:
M1 is_symmetry_circulant_about p
by A1;
width (M1 + M2) = len p
by MATRIX_0:24;
then consider M3 being Matrix of len (p + q),K such that
len (p + q) = width M3
and
A8:
M3 is_symmetry_circulant_about p + q
by A6, A4, A7, Th5;
take
M3
; MATRIX17:def 6 M3 is_symmetry_circulant_about p + q
thus
M3 is_symmetry_circulant_about p + q
by A8; verum