Winter 2012

COMP 6621 Discrete Mathematics of Paul Erdős

4 credits
Students from Québec universities other than Concordia can register for this course through CREPUQ.


  • Course description:
    Paul Erdős (1913 -- 1996) was one of the greatest mathematicians of the twentieth century. He made pre-eminent contributions to number theory, probability theory, real and complex analysis, discrete geometry, approximation theory, and set theory; some say that he founded the field of discrete mathematics.We will study a selection of his results in number theory, geometry, Ramsey theory, extremal combinatorial problems, and graph theory; in doing so, we shall highlight his methods and proof techniques -- such as the probabilistic method -- that are particularly applicable to computer science. From time to time we will stray from his own work to the work of his disciples, but we shall never escape the gravitational pull of the great man.

  • More detailed outline:
    Proof of Bertrand's postulate. The Erdős-Szekeres and the de Bruijn-Erdős theorems. Ramsey's theorem and Ramsey numbers. Property B and hypergraph colouring. Van der Waerden's theorem and van der Waerden numbers. Positional games. The Erdős-Ko-Rado theorem. Delta-systems and a proof of the Erdős-Lovász conjecture. Extremal graph theory. Random graphs and graph colouring. The probabilistic method and its applications in theoretical computer science.
            
The subject and the instructor, ca.1976


Top of this page   •   Sources   •   Bulletin board   •   Material covered in class and homework assignments   •   Erdős links


Top of this page   •   Sources   •   Bulletin board   •   Material covered in class and homework assignments   •   Erdős links

Bulletin board


Top of this page   •   Sources   •   Bulletin board   •   Material covered in class and homework assignments   •   Erdős links

Material covered in class and homework assignments

Date             Material covered                                                                         Homework assignments
Jan 6 Erdős's proof of Bertrand's postulate
Jan 13 Discrete geometry (except for the proof of Theorem 3.1).
Jan 20 Discrete geometry: proof of Theorem 3.1. Ramsey's theorem (up to and including the Greenwood-Gleason colouring on page 4). Homework 1 assigned.
Its solutions.
Jan 27 Ramsey's theorem concluded. Homework 2 assigned
Its solution: these six graphs
Feb 3 Turán's theorem. From Erdős's refinement of this theorem to a theorem on hamiltonian graphs
Feb 10 More on hamiltonian graphs
Feb 17 The Erdős - Stone theorem.
Feb 24 President's Holiday -- University closed
  • Take-home midterm
  • Mar 2
    Mar 9
    Mar 16
    Mar 23
    Mar 30


    Top of this page   •   Sources   •   Bulletin board   •   Material covered in class and homework assignments   •   Erdős links

    The P. G. O. M. and an epsilon


    Top of this page   •   Sources   •   Bulletin board   •   Material covered in class and homework assignments   •   Erdős links


    Top of this page   •   Sources   •   Bulletin board   •   Material covered in class and homework assignments   •   Erdős links

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