Title:
The polymorphic gateway between structure and algorithms: Beyond CSPs

dc.contributor.author Guruswami, Venkat
dc.contributor.corporatename Georgia Institute of Technology. Algorithms, Randomness and Complexity Center en_US
dc.contributor.corporatename Carnegie Mellon University. School of Computer Science en_US
dc.date.accessioned 2018-12-06T17:29:50Z
dc.date.available 2018-12-06T17:29:50Z
dc.date.issued 2018-12-03
dc.description Presented on December 3, 2018 at 11:00 a.m. in the Klaus Advanced Computing Building, Room 1116E. en_US
dc.description Venkatesan Guruswami is a Professor in the School of Computer Science at Carnegie Mellon University. His research interests include several topics in Theoretical Computer Science, including the theory of error-correcting codes, approximation algorithms & non-approximability, pseudorandomness, probabilistically checkable proofs, and algebraic algorithms. en_US
dc.description Runtime: 57:06 minutes en_US
dc.description.abstract What underlying mathematical structure (or lack thereof) in a computational problem governs its efficient solvability (or dictates its hardness)? In the realm of constraint satisfaction problems (CSPs), the algebraic dichotomy theorem gives a definitive answer: a polynomial time algorithm exists when there are non-trivial local operations called polymorphisms under which the solution space is closed; otherwise the problem is NP-complete. Inspired and emboldened by this, one might speculate a broader polymorphic principle: if there are interesting ways to combine solutions to get more solutions, then the problem ought to be tractable (with context dependent interpretations of "interesting" and "tractable”). Beginning with some background on the polymorphic approach to understanding the complexity of constraint satisfaction, the talk will discuss some extensions beyond CSPs where the polymorphic principle seems promising (yet far from understood). Specifically, we will discuss promise CSPs where one is allowed to satisfy a relaxed version of the constraints (a framework that includes important problems like approximate graph coloring and discrepancy minimization), and the potential and challenges in applying the polymorphic framework to them. Another interesting direction is fine-grained complexity, where partial polymorphisms govern the runtime of fast exponential-time algorithms. Our inquiries into these directions also reveal some interesting connections to optimization, such as algorithms to solve LPs over different rings (like integers adjoined with sqrt{2}), and a random-walk based algorithm interpolating between 0-1 and linear programming, generalizing Schöning's famous (4/3)^n time algorithm for 3-SAT. Based on a body of work with Joshua Brakensiek. en_US
dc.format.extent 57:06 minutes
dc.identifier.uri http://hdl.handle.net/1853/60593
dc.language.iso en_US en_US
dc.relation.ispartofseries Algorithms and Randomness Center (ARC) Colloquium
dc.subject Constraint satisfaction problems (CSPs) en_US
dc.subject Polymorphisms en_US
dc.title The polymorphic gateway between structure and algorithms: Beyond CSPs en_US
dc.type Moving Image
dc.type.genre Lecture
dspace.entity.type Publication
local.contributor.corporatename Algorithms and Randomness Center
local.contributor.corporatename College of Computing
local.relation.ispartofseries ARC Colloquium
relation.isOrgUnitOfPublication b53238c2-abff-4a83-89ff-3e7b4e7cba3d
relation.isOrgUnitOfPublication c8892b3c-8db6-4b7b-a33a-1b67f7db2021
relation.isSeriesOfPublication c933e0bc-0cb1-4791-abb4-ed23c5b3be7e
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