| Popis: |
We show that perpendicular arrays exist for arbitrarily large t and with λ = 1. In particular, if d devides ( t +1) then there is a PA 1 (t, t+1, t+( f(t+1) d )) . If υ ≡ 1 or 2 (mod 3) then there is a PA λ (3, 4, υ ) for any λ. If 3 divides λ then there is a PA λ (3, 4, υ ) for any v . If n ⩾2 there is a PA 1 (4, 5, 2 n +1). Using recursive constructions we exhibit several infinite families of perpendicular arrays with t ⩾3 and relatively small λ. We finally discuss methods of constructing perpendicular arrays based on automorphism groups. These methods allow the construction of PA's with ( k − t )>1. |
