combined effects
Recently Published Documents

Graded modal types systems and coeffects are becoming a standard formalism to deal with context-dependent, usage-sensitive computations, especially when combined with computational effects. From a semantic perspective, effectful and coeffectful languages have been studied mostly by means of denotational semantics and almost nothing has been done from the point of view of relational reasoning. This gap in the literature is quite surprising, since many cornerstone results — such as non-interference , metric preservation , and proof irrelevance — on concrete coeffects are inherently relational. In this paper, we fill this gap by developing a general theory and calculus of program relations for higher-order languages with combined effects and coeffects. The relational calculus builds upon the novel notion of a corelator (or comonadic lax extension ) to handle coeffects relationally. Inside such a calculus, we define three notions of effectful and coeffectful program refinements: contextual approximation , logical preorder , and applicative similarity . These are the first operationally-based notions of program refinement (and, consequently, equivalence) for languages with combined effects and coeffects appearing in the literature. We show that the axiomatics of a corelator (together with the one of a relator) is precisely what is needed to prove all the aforementioned program refinements to be precongruences, this way obtaining compositional relational techniques for reasoning about combined effects and coeffects.

Low fit brand extensions, while often presenting profitable opportunities for existing brands, are known to meet with varying levels of consumer acceptance. This research identifies conditions under which low fit extensions can succeed. Specifically, the authors show that the extent to which consumers consider the context in forming judgments (i.e., are context dependent) determines the acceptance of low fit extensions. In four studies, the authors examine the combined effects of context (in)dependence and type of information, and show that context dependent individuals form their evaluations on the basis of the type of brand extension information provided. For context dependent individuals, providing benefit-based information enhances the evaluations of low fit extensions, whereas providing attribute-based information leads to a reliance on extension fit and subsequent unfavorable evaluation of low fit extensions. In contrast, context independent individuals are more likely to base their judgments on extension fit regardless of whether attribute- or benefit-based information is provided. The acceptance of high fit extension is unaffected by context (in)dependence and type of information. Our findings provide a two-step strategy (i.e., sensitizing consumers to context and providing them benefit-based extension information) for managers to successfully launch low fit extensions and leverage existing parent brand equity.