The energy of a graph is equal to the sum of the absolute values of its eigenvalues. Two graphs of the same order are said to be equienergetic if their energies are equal. We point out the following two open problems for equienergetic graphs. (1) Although it is known that there are numerous pairs of equienergetic, non-cospectral trees, it is not known how to systematically construct any such pa...

A common task in literary analysis is to study characters in a novel or collection. When dealing with large documents or collections automatic entity extraction, text analysis and effective user interfaces might facilitate the exploration of the topics discussed or the vocabulary used in the neighborhood of the characters. Using our interface, called POSvis, the scholar uses word clouds and sel...