Darwin and Tinbergen represent two enduring contrasts in comparative cognitive psychology: in the types of behaviors studied and the kinds of explanations sought. Darwin encouraged the search for human-like behaviors in animals as evidence for evolutionary continuity of mental processes. Tinbergen encouraged the careful causal analysis of animal behaviors as such and eschewed interpretations in...

We investigate the representation of functions on streams in some denotational domains. As expected, a total continuous stream function can always be represented by a Scott-continuous function, and moreover by a strongly stable map in the corresponding Hypercoherence. It seems however difficult to represent an arbitrary stream function by a monotone map on Scott domains such that the stream fun...

In this paper we show that a variation of a technique of Mǐskin and Tall yields a cocompact completely regular Moore space that is Scott-domain-representable and has a closed Gδ-subspace that is not Scott-domain-representable. This clarifies the general topology of Scott-domain-representable spaces and raises additional questions about Scott-domain representability in Moore spaces. 2000 AMS Cla...

The primary focus of my research is the computer-aided verification and validation of computer systems, including concurrent and distributed systems; security, network and wireless protocols; software systems; biological systems; and safety-critical and embedded systems. Throughout my career I have been interested in both the computational complexity and algorithmica of verification, striving t...

Let x = {x1, . . . , xr}, y = {y1, . . . , yn}, z = {z1, . . . , zn} be three sets of indeterminates. We give the value of the determinant ∣ ∣ ∣ ∣ ∣ ∏ x∈x (xy − z) ∣ ∣ ∣ ∣ ∣ y∈y,z∈z when specializing y and z to the set of roots of yn − 1 and zn − ξn respectively. In the case where r = 2 and x = {1, 1} the determinant ∣ ∣(y− z) ∣ ∣ y∈y,z∈z factorizes into the determinant of the Cauchy matrix [(y...