# Calendar

Sep
28
Tue
Logic seminar: Janitha Aswedige
Sep 28 @ 10:30 am – 11:30 am

Title: Introduction to Modal Logic: Filtrations and Finite Model Property of $S_5$

Abstract : We’ll introduce some basic notions from Modal Logic namely, Kripke Frames, Standard Models, Filtrations etc. Then we’ll demonstrate the Finite Model Property of the system $S_5$ and this will be our main goal.

Oct
5
Tue
Logic seminar: Janitha Aswedige (part 2)
Oct 5 @ 10:30 am – 11:30 am
Oct
12
Tue
RJ Reiff: Modal logic
Oct 12 @ 10:30 am – 11:30 am
Oct
26
Tue
Logic Seminar: Refuting a generalization of Frankl’s conjecture for lattice-like posets
Oct 26 @ 10:30 am – 11:30 am

Speaker: B. Kjos-Hanssen
Title: Refuting a generalization of Frankl’s conjecture for lattice-like posets

Nov
2
Tue
Logic Seminar: Modal logic of provability (David Webb)
Nov 2 @ 10:30 am – 11:30 am
Nov
9
Tue
David Webb: Kripke semantics for the provability logic GL
Nov 9 @ 10:30 am – 11:30 am
Nov
23
Tue
Logic seminar: Janitha Aswedige
Nov 23 @ 10:30 am – 11:30 am

Janitha Awedige will discuss the paper
“Inference Rules for Probability Logic” by Marija Boricic.

Mar
10
Thu
Oleksandr Markovichenko’s thesis presentation on: Persistent cohomology of cover refinements
Mar 10 @ 3:00 pm – 4:00 pm

Abstract

Topological data analysis (TDA) is a new approach to analyzing complexdata which often helps reveal otherwise hidden patterns by highlightingvarious geometrical and topological features of the data. Persistenthomology is a key in the TDA toolbox. It measures topological featuresof data that persist across multiple scales and thus are robust withrespect to noise. Persistent homology has had many successfulapplications, but there is room for improvement. For large datasets,computation of persistent homology often takes a significant amount oftime. Several approaches have been proposed to try to remedy this issue,such as witness complexes, but those approaches present their owndifficulties.

In this work, we show that one can leverage a well-known data structurein computer science called a cover tree. It allows us to create a newconstruction that avoids difficulties of witness complex and canpotentially provide a significant computational speed up. Moreover, weprove that the persistence diagrams obtained using our novelconstruction are actually close in a certain rigorously defined way topersistent diagrams which we can get using the standard approach basedon Čech complexes. This quantifiable coarse computation of persistentdiagrams has the potential to be used in many applications wherefeatures with a low persistence are known to be less important.