文摘
Let q be a prime power and r,s,m,n positive integers. We construct families of mutually orthogonal gerechte designs of order qr+s with rectangular regions of size qr×qs. This leads to a lower bound on the size of a family of mutually orthogonal gerechte designs of order mn with rectangular regions of size m×n. The construction is linear-algebraic; surrounding theory employs companion matrices and Toeplitz matrices over finite fields.