## (u, u−v, u+v+w)-Construction

Let Ci be (si, Ni, di)-codes over Fb for i = 1, 2, 3 with s1s2s3 and b ≥ 3. For ij let φi,j : FbsiFbsj denote the embedding of Fbsi in Fbsj defined by

φ((x1,…, xsi)) := (x1,…, ssi, 0,…, 0)

and let αFb ∖ {0, 1}. Then the set of vectors

C = {(u, φ1,2(u) + v, φ1,3(u) + αφ2,3(v) + w)  :  uC1,vC2,wC3}

is an (s1 + s2 + s3, N1N2N3, d)-code over Fb with d = min{3d1, 2d2, d3}. If the Ci are linear with Ni = bni, ni×si generator matrices Gi, mi := sini, and mi×si parity check matrices Hi, the generator matrix G of the new linear [s1 + s2 + s3, n1 + n2 + n3, d]-code C is given by

G = ,

its parity check matrix H by

H =

with φi,j(Gi) denoting the ni×sj-matrix (Gi 0ni×(sj-si)) and πj,i(Hj) denoting the first si columns from Hj.

In the context of orthogonal arrays three linear OAs A1, A2, and A3 with parameters OA(bmi, si,Fb, ki) and with generator matrices Hi and s1s2s3 can be used for constructing an OA(bm1+m2+m3, s1 + s2 + s3,Fb, k) with k = min{3k1 +2, 2k2 +1, k3} and generator matrix H, where H is the parity check matrix shown above.

If b ≥ 4, this result can be generalized such that more than three codes are used, leading to the generalized (u, u + v)-construction. The special case where C1 is the trivial [0, 0]-code is identical to the (u, u + v)-construction.