Many multicriteria problems in economics and finance require that efficient solutions be found. A recent contribution to production theory established a characterization of efficient points under closedness and free-disposability (Bonnisseau and Crettez in Econ Theory 31(2):213–223, 2007, Theorem 1). However, as will be shown using a number of examples, these results cannot be applied to simple...

We study mean-variance hedging under portfolio constraints in a general semimartingale model. The constraints are formulated via predictable correspondences, meaning that the trading strategy is restricted to lie in a closed convex set which may depend on the state and time in a predictable way. To obtain the existence of a solution, we first establish the closedness in L2 of the space of all g...

There is a widespread interest in doctoral supervision, yet novice co-supervisors’ experiences remain understudied. The aim of this qualitative study to explore how supervision culture and practice are experienced by novices. This thematic analysis based on focus groups in-depth interviews with 23 co-supervisors from two Swedish research-intensive universities. reveals three dimensions related ...

The notion of communication closed layer has been introduced as a way to define structured composition of distributed sy~tems. An interesting question is how to verify the closedness of a layer. We formulate a proof rule proving closed ness of a distributed layer. The rule is developed as an extension of the Apt. Francez and de Roever proof system for CSP. The extension is proved to be sound an...

Keywords: Exponential subcategory of a category, cartesian closed category, initially structured category, category of partial algebras of the same type, partial algebra fulllling the interchange law, diagonal partial algebra. Abstract: We study categories of partial algebras of the same type. In these categories we deene a binary operation of exponentiation for objects and investigate its beha...