Category Research

The densest subgraph problem with negative weights

Few days ago I uploaded on Arxiv our preprint “Novel Dense Subgraph Discovery Primitives: Risk Aversion and Exclusion Queries”.  This is joint work with Tianyi, Nao, and Jakub. In this paper we study the following extension of the densest subgraph problem (DSP) that is known to be solvable exactly in polynomial time on graphs with […]

Graph mining with a faulty oracle

Pythia was a powerful and respected woman in Ancient Greece. She was the high priestess of the Temple of Apollo at Delphi. I was surprised to read in the Wikipedia article that the name Pythia is derived from the verb πύθειν (púthein) which means “to rot”; I find this to be unlikely. An etymology that sounds […]

Risk aversion and uncertain graphs

     Let’s say that you have 100$ and you want to invest your money wisely. There are two hedge funds that interest you, both of which have the same expected return. How should you invest your 100$? Does it matter if you split it in half, or if you invest all of your money […]