We present a refinement, suggested by Jensen and Milner under the term kind, of pure bigraphs. We name the result kind bigraphs. This refinement generalises the notion of atomic and non-atomic controls, allowing a control to contain a subset of the set of controls. We show that this variation has relative pushouts and classify its idem pushouts. A canonical labelled transition system can be der...

In this paper we study network competition when costs differ among interconnected networks. Such cost differences are observed in the mobile sector as well as in fixed networks. In the paper we find that cost based regulation will not result in first best market shares. The low cost firm will be too small in equilibrium. This is partly due to tariff mediated network externalities. This result i...

In this paper we extend the results of recent studies on the existence of equilibrium in finite dimensional asset markets for both bounded and unbounded economies. We do not assume that the individual’s preferences are complete or transitive. Our existence theorems for asset markets allow for short selling. We shall also show that the equilibrium achieves a constrained core within the same fram...

SFS (Shape From Shading) theory is based upon the Lambertian paradigm. Our visual demonstrations imply that this paradigm fails to apply to the conventional stimuli used to probe vision.

We examine the impacts of resale opportunity on entry and bidding strategies in simultaneous bidding process (auction mechanism) and sequential bidding process (sequential mechanism) with costly entry, and relative performance between the two mechanisms. Resale opportunity reinforces the partial-pooling equilibrium that a bidder submits a jump bid (even higher than his value) to deter following...