The Robinson-Foulds (RF) metric is arguably the most widely used measure of phylogenetic tree similarity, despite its well-known shortcomings: For example, moving a single taxon in a tree can result in a tree that has maximum distance to the original one; but the two trees are identical if we remove the single taxon. To this end, we propose a natural extension of the RF metric that does not sim...

In this chapter I follow the evolution of Joan Robinson’s appreciation of Sra¤a’s “critique of economic theory”over the years. My purpose is twofold: …rst, to construct a narrative based also on the archival …ndings; second, to shed some light on certain dividing issues–as we shall see in the …nal section– which impinged on the fortunes of the “Cambridge school”, in search of a clue to explain ...

A class of solutions of the low energy string theory in four dimensions is studied. This class admits a geodesic, shear-free null congruence which is non-twisting but in general diverging and the corresponding solutions in Einstein's theory form the Robinson-Trautman family together with a subset of the Kundt's class. The Robinson-Trautman conditions are found to be frame invariant in string th...