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What and Who
Title:On Rationality of Nonnegative Matrix Factorization
Speaker:James Worrell
coming from:University of Oxford
Speakers Bio:James Worrell is a Professor of Computer Science at the University of Oxford.  He currently holds on an EPSRC Established Career Fellowship on the subject of Verification of Linear Dynamical Systems.
Event Type:SWS Distinguished Lecture Series
Visibility:D1, D2, D3, D4, D5, SWS, RG1, MMCI
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Level:Expert Audience
Language:English
Date, Time and Location
Date:Tuesday, 2 May 2017
Time:10:30
Duration:60 Minutes
Location:Saarbrücken
Building:E1 5
Room:002
Abstract
The nonnegative rank of a nonnegative m x n matrix M is the smallest number d such that M can be written as the product M = WH of a nonnegative m x d matrix W and a nonnegative d x n matrix H.  The notions of nonnegative rank and nonnegative matrix factorization have a wide variety of applications, including bioinformatics, computer vision, communication complexity, document clustering, and recommender systems. A longstanding open problem is whether, when M is a rational matrix, the factors W and H in a rank decomposition M=WH can always be chosen to be rational.  In this talk we resolve this problem negatively and discuss consequences of this result for the computational complexity of computing nonnegative rank.

This is joint work with Dmitry Chistikov, Stefan Kiefer, Ines Marusic, and Mahsa Shirmohammadi.

Contact
Name(s):Brigitta Hansen
Phone:0681 93039102
EMail:--email address not disclosed on the web
Video Broadcast
Video Broadcast:YesTo Location:Kaiserslautern
To Building:G26To Room:112
Meeting ID:
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Attachments, File(s):
  • Brigitta Hansen, 03/29/2017 02:31 PM -- Created document.