Abstract
Using the terminology in 2 (where the expression m-type is also explained) we will prove the following theorems: Theorem 1. If there exist (i) a skew-Hadamard matrix H = U+I of order h, (ii)m-type matrices M = W+I and N = NT of order m, (iii) three matrices X, Y, Z of order x = 3 (mod 4) satisfying (a) XYT, YZT and ZXT all symmetric, and (b) XXT = aIx+bJx then is an Hadamard matrix of order mxh.

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