The Math/Stats Colloquium brings the fall semester to an exciting conclusion with Ruriko Yoshida (Naval Postgraduate School) on “Evolution and Triangles in Tree Spaces”.  A phylogenetic tree, also known as an evolutionary tree, is a tree representation of evolutionary history among different species.  Since Charles Darwin illustrated the notion of an evolutionary tree, such trees have provided a great statistical model to learn the evolutionary history of biological data.  Motivated by statistical analysis on a set of phylogenetic trees, we are interested in the space of all possible phylogenetic trees with a given number of species.  In this talk we will discuss some properties of triangles in this space.  (Joint with B. Lin, B. Sturmfels, and X. Tang)

Background: One semester linear algebra.  Interest in geometry, statistics, or computational biology is helpful but not necessary.

• Date: Fri Dec 09
• Time: 2:30-3:20pm
• Room: MH320
• Snacks: 2:00pm in MH331B

For more information, click here to see the full flyer, suitable for printing and posting.

Hope to see you there!

The Math/Stats Colloquium is pleased to present the penultimate talk of the fall semester: Ian Leary (Univ. of Southampton, visiting MSRI) on “Almost finitely presented groups and their subgroups”.  A presentation is a way of describing a group.  In the 1960’s Higman found a deep connection between subgroups of finitely presented groups and computation.  In the 1990’s Bestvina and Brady found the first non-finitely presented groups that were almost finitely presented.  The speaker has recently found a lot more, and an analog of Higman’s theorem but for almost finitely presented groups; the talk will describe this progress.

Background: One semester abstract algebra.

• Date: Fri Dec 02
• Time: 2:30-3:20pm
• Room: MH320
• Snacks: 2:00pm in MH331B

For more information, click here to see the full flyer, suitable for printing and posting.

Hope to see you there!

Upcoming events:

• Fri Dec 02: Department meeting
• Fri Dec 09: Ruriko Yoshida, Naval Postgraduate School
  “Evolution and Triangles in Tree Spaces”

The Math/Stats Colloquium resumes its regular schedule with Tullia Dymarz (U. Wisconsin) telling us all how to “Get rich fast!*”  A Ponzi scheme is a way of shuffling around money among friends and neighbors so that everyone ends up with more money than they started with.  Obviously this is an impossible feat with only finitely many people with a finite amount of cash (even though it has been attempted many times throughout history).  This talk will discuss Ponzi schemes on infinite graphs, with the goal of characterizing those graphs that admit Ponzi schemes and those that do not.

* = Offer available only on non-amenable graphs

Background: No particular background necessary.

• Date: Fri Nov 18
• Time: 2:30-3:20pm
• Room: MH320
• Snacks: 2:00pm in MH331B

For more information, click here to see the full flyer, suitable for printing and posting.

Hope to see you there!

Upcoming events:

• Fri Nov 25: NO COLLOQUIUM (Happy Thanksgiving!)\
• Fri Dec 02: Department meeting
• Fri Dec 02: Ian Leary, Univ. of Southampton/MSRI
  “Almost finitely presented groups and their subgroups”
• Fri Dec 09: Ruriko Yoshida, Naval Postgraduate School
  “Evolution and Triangles in Tree Spaces”

The Math/Stats Colloquium is pleased to present the grand finale of our series of new faculty colloquia: Yan Zhang on “Voting Theory ‘Theorems’ and Misapplied Math”.  Voting theory is an interdisciplinary (math, economics, social science) field studying how to combine the preferences of many voters into a single preference (such as elected representatives or policy).  This talk discusses some classical results and show how they can be applied and misapplied, focusing on the celebrated Arrow’s Theorem and the slightly less-well-known May’s Theorem, both “theorems” about how innocuous constraints on a voting system can force it to have certain restrictive, and often very strange, properties.  Our focus is not on the proofs but on the intuition the theorems give.  We also discuss work in progress (joint with Mahendra Prasad, UC Berkeley) about a generalization of May’s Theorem and implications for the social sciences.

Background: No particular background required; no prior familiarity with voting theory assumed.

• Date: Fri Oct 28
• Time: 2:30-3:20pm
• Room: MH320
• Snacks: 2:00pm in MH331B

For more information, click here to see the full flyer, suitable for printing and posting.

Hope to see you there!

Upcoming events:

• Next colloquium, Fri Nov 18:  Tullia Dymarz (U. Wisconsin)
  “Get rich fast!*”

  (* – offer available only on non-amenable graphs)

The Math/Stats Colloquium is excited to present the third of our four new assistant professors, Wesley Maciejewski, on “Mathematical Foresight: Thinking in the Future to Work in the Present”.  How do users of mathematics solve mathematical problems?  The automaticity of solving a basic derivative-finding task and the schema evoked during less routine problems are familiar, but this presentation will focus on another process: Mathematical Foresight.  Mathematicians solving unfamiliar, non-routine problems often imagine a resolution to the problem and a path leading to that resolution.  This amounts to imagining the problem in a future state, and this future thinking guides the mathematician’s present work forward.  This talk will present the main features of this process alongside evidence of mathematicians and students engaging in it.

Background: No particular background necessary.

• Date: Fri Oct 21
• Time: 2:30-3:20pm
• Room: MH320
• Snacks: 2:00pm in MH331B

For more information, click here to see the full flyer, suitable for printing and posting.

Hope to see you there!

Upcoming events:

• Fri Oct 28: Department meeting
• Fri Oct 28: Yan Zhang, SJSU
  “Voting Theory ‘Theorems’ and Misapplied Math”
• Next colloquium after that: Fri Nov 18