let n be Element of NAT ; :: thesis: for K being Field
for a, b, c being Element of K
for M1, M2, M3 being Matrix of n,K st M1 is col_circulant & M2 is col_circulant & M3 is col_circulant holds
((a * M1) - (b * M2)) + (c * M3) is col_circulant

let K be Field; :: thesis: for a, b, c being Element of K
for M1, M2, M3 being Matrix of n,K st M1 is col_circulant & M2 is col_circulant & M3 is col_circulant holds
((a * M1) - (b * M2)) + (c * M3) is col_circulant

let a, b, c be Element of K; :: thesis: for M1, M2, M3 being Matrix of n,K st M1 is col_circulant & M2 is col_circulant & M3 is col_circulant holds
((a * M1) - (b * M2)) + (c * M3) is col_circulant

let M1, M2, M3 be Matrix of n,K; :: thesis: ( M1 is col_circulant & M2 is col_circulant & M3 is col_circulant implies ((a * M1) - (b * M2)) + (c * M3) is col_circulant )
assume ( M1 is col_circulant & M2 is col_circulant & M3 is col_circulant ) ; :: thesis: ((a * M1) - (b * M2)) + (c * M3) is col_circulant
then ( c * M3 is col_circulant & (a * M1) - (b * M2) is col_circulant ) by Th20, Th27;
hence ((a * M1) - (b * M2)) + (c * M3) is col_circulant by Th21; :: thesis: verum