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Logic and Computation Seminar

Monday, November 18, 2013 - 3:30pm

Lynn Scow

Vassar

Location

University of Pennsylvania

4C8

Fix any structure I on an underlying set I. An I-indexed indiscernible set is a set of parameters A = {a_i : i in I} where the a_i are same- length finite tuples from some structure M and A satisfies a certain homogeneity condition. In this talk, I will discuss examples of trees I for which I-indexed indiscernible sets are particularly well-behaved. In particular, we will look at the structure I_0 = (omega^{< omega},unlhd,lx,wedge) where unlhd is the partial order on the tree, wedge is the meet in this order, and lx is the lexicographical order. By a dictionary theorem that I will present in this talk, known results about indiscernibles from model theory yield alternate proofs that certain classes of finite trees are Ramsey.