Universal Algebra seminar

David McLaughlin, Department of Pure Mathematics, University of Waterloo

"Projective Posets"

A poset is said to be projective if its only idempotent polymorphisms  
are projections. We will try to classify projective posets using  
combinatorial properties. Projective posets of height 1 are completely  
understood. Moreover, we know exactly when posets of height 1 have  
Taylor polymorphisms. We will also discuss known results about posets  
of greater height.