This generalizes a result of Hughes [4, 5], who proved Theorem 1 when the plane has order ~ 250. Our proof essentially amounts to formalizing Hughes' approach, and then applying results on the structure of a finite ~ o u p having a nontrivial normal parti t ion [1, 2, 7]. Coordinatizing a plane of type I-4 in the usual manner with U = A, V ---B, and 0 = C (see [3, w 3.1]), we obtain a linear pl...

one of unsolved problems in quantum measurement theory is to characterize coexistence of quantum effects. in this paper, applying positive operator matrix theory, we give a mathematical characterization of the witness set of coexistence of quantum effects and obtain a series of properties of coexistence. we also devote to characterizing bijective morphisms on quantum effects leaving the witness...

UNLABELLED Most studies concerning psychological measurement scales of intensive attributes have concluded that these scales are of ratio type and that the psychophysical function is closely approximated by a power function. Experiments show, for such cases, that a commutativity property must hold under either successive increases or successive decreases provided, e.g., all other independent di...

In this paper we study the structure and the commutativity of a ring R, in which for each x,y ? R, there exist two integers depending on x,y such that [x,y]k equals x n or y n.

Commutativity has the same inherent limitations as compatibility. Then, it is worth conceiving simple concurrency control techniques. We propose a restricted form of commutativity which increases parallelism without incurring a higher overhead than compatibility. Advantages of our proposition are: (1) commutativity of operations is determined at compile-time, (2) runtime checking is as efficien...