A Nasty Act?

Some Nasty Reflexive Groups

In Almost Free Modules, Set-theoretic Methods, Eklof and Mekler [5, p. 455, Problem 12] raised the question about the existence of dual abelian groups G which are not isomorphic to Z ⊕G. Recall that G is a dual group if G ∼= D for some groupD withD = Hom (D,Z). The existence of such groups is not obvious because dual groups are subgroups of cartesian products Z and therefore have very many homo...

No more Mr Nasty.

A s my 6-year term as Chief Editor of EMBO Reports draws to its close, I think it’s time to offer a personal reflection on what it’s like to have been in what some may think of as one of the most hated positions in academic science. I consider myself lucky that at least a handful of colleagues are still speaking both to me and to my team of professional editors in Heidelberg, who do all the wor...

Point Sets Can Have Nasty

The Pleasure of Being Nasty

Many laboratory experiments show that people are often altruistic or care for fairness. We present data that reveal a darker side of human nature. We introduce the joy-of-destruction game. Two players each receive an endowment and simultaneously decide on how much of the other player’s endowment to destroy. Subjects play this game repeatedly. In one treatment, subjects can hide their destructio...

PAC Learning with Nasty Noise

We introduce a new model for learning in the presence of noise, which we call the Nasty Noise model. This model generalizes previously considered models of learning with noise. The learning process in this model, which is a variant of the PAC model, proceeds as follows: Suppose that the learning algorithm during its execution asks for m examples. The examples that the algorithm gets are generat...