We define an n-type (1, -1) matrix N = 1 + R of order n ~ 2 (mod 4) to have R symmetric and R2 = (n - 1)/n. These matrices are analogous to skewtype matrices M = 1 + W which have W skew-symmetric.
History
Citation
Jennifer Seberry Wallis, Some (1, -1) matrices, Journal of Combinatorial Theory, Ser. B., 10, (1971), 1-11.
