Department of Mathematics and Computer Science
Number Theory and Combinatorics Seminar
Fall 2023
For more information, contact Félix Baril Boudreau <>
or Ertan Elma <>.

Talks are usually at 2pm on Tuesday in room M1060 (Markin Hall). All times are Mountain Time.
The live access zoom link is available here and on, and is also sent to our mailing list.
                  The next talk:

Oct 3
at 2pm
in M1060
Kübra Benli
(University of Lethbridge)  
Sums of proper divisors with missing digits
In 1992, Erdős, Granville, Pomerance, and Spiro conjectured that if $\mathcal{A}$ is a set of integers with asymptotic density zero then the preimage of $\mathcal{A}$ under $s(n)$, sum-of-proper-divisors function, also has asymptotic density zero. In this talk, we will discuss the verification of this conjecture when $\mathcal{A}$ is taken to be the set of integers with missing digits (also known as ellipsephic integers) by giving a quantitative estimate on the size of the set $s^{-1}(\mathcal{A})$. This is joint work with Giulia Cesana, Cécile Dartyge, Charlotte Dombrowsky and Lola Thompson.
Click on any title for more info, including the abstract. Then click on it again to hide the info.
When available, click on the mathtube icon     to access a videorecording of the talk.

Date Speaker Title

Sept 12 everyone Organizational meeting and problem session

Sept 19 Gabriel Verret Vertex-transitive graphs with large automorphism groups
(University of Auckland, New Zealand)

Sept 26 Sedanur Albayrak Quantitative estimates for the size of an intersection of sparse automatic sets
(University of Calgary)

Oct 3 Kübra Benli Sums of proper divisors with missing digits

Oct 12 Wanlin Li Basic reductions of abelian varieties
(Washington University, St. Louis)

Oct 17 Hiva Gheisari Title TBA

Oct 25 Yu-Ru Liu Title TBA
(University of Waterloo)

Oct 31 Joy Morris Easy detection of (Di)Graphical Regular Representations

Nov 7 Abbas Maarefparvar Title TBA

Nov 21 Sreerupa Bhattacharjee Title TBA

Nov 28 Ha Tran Title TBA
(Concordia University of Edmonton)

Dec 5 Speaker TBA Title TBA

Past semesters: Fall F07 F08 F09 F10 F11 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22
Spring S08 S09 S10 S12 S13 S14 S15 S16 S17 S18 S19 S20 S21 S22 S23
Click here for a PDF file of abstracts of all talks back to 2007 (approx 450K).