We derive self-reciprocity properties for a number of polyomino generating functions, including several families of column-convex polygons, three-choice polygons and staircase polygons with a staircase hole. In so doing, we establish a connection between the reciprocity results known to combinatorialists and the inversion relations used by physicists to solve models in statistical mechanics. Fo...

For a convex polytope P with rational vertices, we count the number of integer points in integral dilates of P and its interior. The Ehrhart-Macdonald reciprocity law gives an intimate relation between these two counting functions. A similar counting function and reciprocity law exists for the sum of all solid angles at integer points in dilates of P . We derive a unifying generalization of the...

Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamen...

Strong reciprocity, defined as a predisposition to help others and to punish those that are not helping, has been proposed as a potent force leading to the evolution of cooperation and altruism. However, the conditions under which strong reciprocity might be favored are not clear. Here we investigate the selective pressure on strong reciprocity by letting both limited dispersal (i.e., spatial s...

The strong reciprocity model of the evolution of human cooperation has gained some acceptance, partly on the basis of support from experimental findings. The observation that unfair offers in the ultimatum game are frequently rejected constitutes an important piece of the experimental evidence for strong reciprocity. In the present study, we have challenged the idea that the rejection response ...

This article develops a reciprocity ethics of the environment through a discussion of ethnobotanical medicines used in the treatment of cancer. The moral virtue of reciprocity, defined as the returning of good when good is received or anticipated, is central to the posthumanist rethinking of human relationships to the plant world. As herbal medicines are used progressively more around the globe...

A defining aspect of human cooperation is the use of sophisticated indirect reciprocity. We observe others, talk about others, and act accordingly. We help those who help others, and we cooperate expecting that others will cooperate in return. Indirect reciprocity is based on reputation, which spreads by communication. A crucial aspect of indirect reciprocity is observability: reputation effect...

Reciprocity and Payment Schemes: When Equality Is Unfair A growing literature stresses the importance of reciprocity, especially for employment relations. In this paper, we study the interaction of different payment modes with reciprocity. In particular, we analyze how equal wages affect performance and efficiency in an environment characterized by contractual incompleteness. In our experiment,...