Winter 2008
Seminar this term will meet Fridays at 2:00 pm in Kemeny 008.
| Date | Speaker | Title |
|---|---|---|
| Jan 18 |
Jared Corduan
Dartmouth College
|
Recursion theoretic analysis of the Nash Williams Barrier Partition Theorem |
| Jan 25 |
Jared Corduan
Dartmouth College
|
$\omega^{\omega}$ is a partition ordinal |
| Feb 8 |
Jared Corduan
Dartmouth College
|
A partition result of Erdos and Milner |
| Feb 15 | No seminar this week - Penelope Maddy will be giving a joint math/philosophy colloquium at 4. | |
| Feb 22 |
Mia Minnes
Cornell University
|
Complexity of tree questions based on their presentations How hard is it to tell if two trees are isomorphic? We use isomorphism invariants to place this question on the analytical hierarchy for different classes of trees (namely, recursive partial order trees, automatic partial order trees, and automatic successor trees). This is joint work with Bakhadyr Khoussainov. |
| Feb 29 |
Asher Kach
University of Connecticut
|
Computable embeddings of computable linear orders In this talk, we'll discuss what the existence of a classical embedding between computable linear orders implies about the complexity (from a computability viewpoint) of such embeddings. Specifically, we'll demonstrate the existence of a non-scattered linear order having no computable presentation into which the rationals computably embed; and the existence of a non-well-ordered linear order having no computable presentation into which the negative integers computably embed. As time permits, we'll sharpen these results by increasing the minimal complexity of any embedding and by demonstrating the minimality (in terms of rank) of the examples presented. This work is joint with Joe Miller and Reed Solomon. |
| Mar 7 |
Brooke Andersen
Dartmouth College
|
Sets that fail to be $D$-complete |
| Mar 21 |
Francois Dorais
Cornell University
|
Class forcing in small universes |