  A completely non-generous and reciprocal population of players can create a
robust cooperating state that cannot be invaded by always defecting free riders
if the interactions among players are repeated for long enough. However, strict
non-generosity and strict reciprocity are ideal concepts, and may not even be
desirable sometimes. Therefore, to what extent generosity or non-reciprocity
can be allowed while still not be swamped by the mutants, is a natural
question. In this paper, we not only ask this question but furthermore ask how
generosity comparatively fares against non-reciprocity in this context. For
mathematical concreteness, we work within the framework of multiplayer repeated
prisoner's dilemma game with reactive strategies in a finite and an infinite
population; and explore the aforementioned questions through the effects of the
benefit to cost ratio, the interaction group size, and the population size.
