Schedule

Date Materials Topics
September 30 Lecture 1.pdf
  • What is a proof? (Section 1.1)
  • Proof complexity definition (Section 1.2)
  • Resolution and equivalence of DPLL and Tree Resolution (Section 1.3)
October 5 Lecture 2.pdf
  • Ordered and Regular Resolution (Section 1.3)
  • Tseitin formulas (Section 1.6)
  • Frege proofs (Section 1.3)
  • Extended Frege and Extended Resolution (Section 1.3)
  • C-Frege proofs for circuit complexity class C (Section 1.3)
  • Hierarchy of logical proof systems
  • Nullstellensatz proofs (Section 1.4)
October 6 exercises1.pdf - First exercises due Friday October 16 (submit via Canvas)
October 7 Lecture 3.pdf
  • Nullstellensatz proofs (Section 1.4)
  • Dual variables (Section 1.4)
  • Finding low degree Nullstellensatz proofs (Section 1.4)
  • Polynomial Calculus (PC) proofs (Section 1.4)
  • PCR, PC with dual variables, simulates resolution (Section 1.4)
  • Finding low degree PC and PCR proofs (Section 1.4)
  • Pigeonhole Principle (Section 1.6)
  • Start of exponential lower bound for PHP in resolution (Section 2.1)
October 12 Lecture 4.pdf
  • Exponential lower bound for PHP in resolution (Section 2.1)
  • Resolution width and conversion of small tree-like proofs to small width proofs (Section 2.2)
October 13 exercises2.pdf - Exercise due Friday October 23 (submit via Canvas)
October 14 Lecture 5.pdf
  • Small size resolution proofs imply small width proofs (Section 2.2)
  • Width-based resolution proof search for small size proofs (Section 2.2)
  • Boundary expansion and lower bounds on resolution proof width (Section 2.3)
October 19 Lecture 6.pdf
  • Large bipartite expansion implies boundary expansion (Section 2.3)
  • Random k-CNF formulas and their unsatisfiability threshold (Section 1.6)
  • Random k-CNF formulas typically have large bipartite expansion (yielding resolution width and proof size lower bounds) (Section 2.4)
October 21 Lecture 7.pdf
  • More applications of width lower bounds for Resolution (Section 2.5)
  • Alternative characterizations of subclasses of Resolution proofs (Section 2.6)
October 26 Lecture 8.pdf
  • Algebraic proofs non-clausal translations and low-degree Nullstellensatz proofs (Section 3.1)
  • d-designs and degree lower bounds for Nullstellenstz proofs (Section 3.2)
  • Degree lower bounds for Induction Principle and Pebbling formulas (Section 3.2)
  • Size-degree relationship for PC and PCR proofs (Section 3.3)
  • Gaussian width (Section 3.4)
October 28 Lecture 9.pdf
  • Gaussian Width (Section 3.4)
  • Polynomial Calculus over the ±1 basis and equivalence of degree with ordinary PC proofs (Section 3.4)
  • Equivalence of zeroes of binomial polynomials over ±1 basis and mod-2 Gaussian equations (Section 3.4)
  • PC refutations of binomials over &\plusmn;1 basis can always be binomial (Section 3.4)
  • PC degree of refutations of binomials is at least 1/2 Gaussian width (Section 3.4)
  • PC degree and PCR size lower bounds for Tseitin formulas (Section 3.4)
  • PC degree and PCR size lower bounds for random k-CNF formulas (Section 3.4)
November 1 exercises3.pdf - Exercises due Friday November 13 (submit via Canvas)
November 2 Lecture 10.pdf
  • Semi-Algebraic proof systems (Section 1.5)
  • Cutting Planes (Section 1.5)
  • Cutting Planes efficiently simulates Resolution (Section 1.5)
  • Efficient Cutting Planes proofs of Pigeonhole formulas (Section 1.6)
November 4 Lecture 11.pdf
  • CDCL solvers (and relationship with resolution) (Section 1.3)
November 9 Lecture 12.pdf
  • Pseudo-Boolean solvers and Cutting Planes implementation (Section 1.5)
  • Sherali-Adams proofs (Section 1.5)
November 16 Lecture 13.pdf
  • Sherali-Adams proofs review (Section 1.5)
  • Sherali-Adams simulates resolution (Section 1.5)
  • Sum-of-Squares (SoS) proofs (Section 1.5)
  • SoS proofs of the pigeonhole principle (Section 1.6)
  • Sos simulates polynomial calculus over the reals (Section 1.5)
November 18 Lecture 14.pdf
  • Sum-of-Squares (SoS) proof search (Section 1.5)
  • Relating Sherali-Adams and SoS to LP and SDP (Section 1.5)
  • Intro to communication complexity (Section 4.1)
November 23 Lecture 15.pdf
  • Two-party and multiparty communication complexity (Section 4.1)
  • Multiparty communication complexity of polynomial inequalities (Section 4.2)
  • Tree-like proofs and communication complexity of SearchF (Section 4.2)
  • Lower bounds for low degree tree-like proofs for Positivstellensat Calculus (and resolution and cutting planes) (Section 4.2)
November 25 Lecture 16.pdf
  • Resolution lower bound via feasible interpolation (Section 4.3)
  • Cutting Planes lower bound via feasible interpolation (Section 4.3)
November 30 Lecture 17.pdf
  • Semantic Cutting Planes proofs and triangle DAGs (not yet in notes)
  • Lifted formulas via Index gadget (not yet in notes)
  • Lower bounds for semantic CP lifted from resolution width (not yet in notes)
  • Pseudo-expectation definitions for Sherali-Adams and SoS (see Fleming, Kothari, Pitassi)
  • Pseudo-expectations imply degree lower bounds for Sherali-Adams and SoS (see Fleming, Kothari, Pitassi)
December 1 exercises4.pdf - Exercises due Friday December 18 (submit via Canvas)
December 2 Lecture 18.pdf
  • Pseudo-expectation for Sherali-Adams and LP solutions (see Fleming, Kothari, Pitassi)
  • Pseudo-expectation for SoS and SDP solutions (see Fleming, Kothari, Pitassi)
  • Ellipsoid algorithm for convex programming (see Flemining, Kothari, Pitassi)
  • Degree 2 SoS and MAXCUT (see Fleming, Kothari, Pitassi)
  • Unique Games Conjecture and degree 2 SoS for MAXCSP (see Fleming, Kothari, Pitassi)
  • Pseudo-expectation for SoS over {+1,-1} variables (see Fleming, Kothari, Pitassi)
December 7 Lecture 19.pdf
  • Pseudo-expectations for linear constraints below Gaussian width (see Flemin, Kothari, Pitassi: Section 5.1)
  • Linear SoS degree and exponential size lower bounds for random k-CNF, random k-XOR, Tseitin on expanders (see Fleming, Kothari, Pitassi: Section 5.2)
  • Pseudo-expectation for Knapsack (see sumofsquares.org notes)
  • Extension complexity for LP, SDP (see Fleming, Kothari, Pitassi)
  • Lower bounds for LP, SDP extensions of MAXCSP in terms of SA and SoS degree (see Fleming, Kotheri, Pitassi)
December 9 Lecture 20.pdf
  • NP-hardness for finding sub-exponential approximation to optimal proof size for Resolution, Cutting Planes, NS, PC, SA, Regular resolution, Ordered Resolution.
  • DRAT proof system and its use in practice to check complete SAT solvers.
  • AC0-Frege proof lower bounds.
  • Open problems.