If T is an operator on a Hubert space %, this paper gives necessary and sufficient conditions on 7" such that C*(T), the C*-algebra generated by T, is generated by a unilateral shift of some multiplicity. This result is then specialized to the cases in which T is a hyponormal or subnormal operator. In particular, it is shown how to prove a recent conjecture of C. R. Putnam as a consequence of o...

We have examined the extent to which ethnic diversity in neighbourhoods and municipalities in The Netherlands is related to personal contact with neighbours from ethnic in-groups and out-groups among the native majority as well as among ethnic minorities. The results indicate that ethnic diversity is negatively related to personal contacts with native neighbours, but positively to personal cont...

An asymmetric Fuglede-Putnam’s Theorem for w−hyponormal operators and class Y operators is proved, as a consequence of this result, we obtain that the range of the generalized derivation induced by the above classes of operators is orthogonal to its kernel.

1. Although this remark does not apply to Laidlaw, who recognizes to a considerable extent the value and relevance of scientific enquiry. Scientific explanations and interpretive accounts of human behaviour, including religious behaviour, are different kinds of enterprise. It is tempting to think that although the questions asked by both scientists and humanist scholars look similar, they are a...

Everett-DeWitt interpretations of quantum physics speak of a multiplicity of physically coexisting worlds. These imaginative reactions to the conceptual problems of standard quantum mechanics form a family of physicalist “many-worlds” proposals (PMW for short) that have been variously dismissed as “incoherent”, so far without full success. A renewed charge by Hilary Putnam now seems to pose dee...