We consider a version of PCF, and prove, using both syntactic and semantic means, that the op-erational equivalences of the base language are preserved when the language is extended with sum andproduct types, with polymorphic types, and with recursive types. These theorems show that the additionsto the type systems are orthogonal to the original language.

The main purpose of this note is to characterize the operators T ∈ B(H) which are orthogonal (in the sense of James) to the range of a generalized derivation for non-normal operators A,B ∈ B(H).

There has for longer been an interest in finding equivalent conditions which define inner product spaces, and the respective literature is considerable, see for instance Amir, which lists 350 such results. Here, in this tradition, an alternative definition of orthogonality is presented which does not make use of any inner product. This definition, in the spirit of the recently developed non-wel...

Sobolev orthogonality has been studied for years. For different families of polynomials, there exist several results about recurrence relations, asymptotics, algebraic and differentation properties, zeros, etc. (see, for instance, Alfaro et al. (1999), Jung et al. (1997), Kwon and Littlejohn (1995, 1998), Marcellán et al. (1996), Pérez and Piñar (1996)); but there exist very few results establi...

Abstract: A Latin square arrangement is an arrangement of s symbols in s rows and s columns, such that every symbol occurs once in each row and each column. When two Latin squares of same order superimposed on one another, then in the resultant array every ordered pair of symbols occurs exactly once, then the two Latin squares are said to be orthogonal. A frequency square M of type F (n; λ) is ...

We produce the first example of bounding total variation distance to stationarity and estimating mixing times via orthogonal polynomials diagonalization of discrete reversible Markov chains, the Karlin-McGregor approach.