Forbidden configurations in the linear lattices

03/01/2016 - 12:15pm
03/01/2016 - 1:10pm
Song Yu (Pomona College)

Lines and planes that go through the origin are subspaces of the three-dimensional Euclidean space R^3. We can easily draw one million lines and one million planes in a way that none of the lines are contained in any of the planes. If we replace the real numbers with the finite field F_2, we still can have a three-dimensional space and lines and planes through the origin, but the largest collection of lines and planes where none of the lines are on any of the planes has size 7. In this talk, we will explore forbidden configurations among subspaces of a finite dimensional vector space over a finite field. We will highlight the analogy between subspaces of a vector space and subsets of a set and see how our problems fit into the general investigation of maximal subposets with certain constraints, a fruitful area of research starting from the classical Sperner's Theorem.

Millikan 2099, Pomona College