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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 […]

Arthur Ganson

For those in Boston, visit the MIT Museum. Amazing machines at exhibition all created by Arthur Ganson, including this (funny) one: Here you can hear Arthur Ganson talking about his machines at a TED event.

Denoising binary images

Data science is transforming the world: we already see self-driving cars moving from research to production, data-driven cancer diagnostic systems, machine learning trader bots and lots of other exciting technologies because the corresponding problems have been reduced to understanding data. While the science of data for centuries was known as statistics, computer scientists, together 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 […]

Nevanlinna Prize 2018

Costis Daskalakis has won this year the Rolf Nevanlinna Prize. This is a great distinction for Costis that recognizes the high quality, depth, breadth, and impact of his research work.  Quanta Magazine has a very nice article about Costis that is worth reading. Συγχαρίκια Κωνσταντίνε! Πάντα τέτοια.   Update Sept. 6th: Yesterday at MIT we celebrated […]

WWW 2018

I am blogging from Lyon where I find myself for the Web Conference 2018.  So far, I’ve attended many interesting talks. I enjoyed a lot Jon Kleinberg’s talk on procrastination. George Akerlof noticed that instead of sending a package by mail with one time-effort of cost , he preferred to postpone this every day until […]

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 […]