5/2015:15

Henri Mühle (TU Dresden)

TITLE: Refined Face Enumeration in v-Associahedra

ABSTRACT: Chapoton defined for each finite root system three remarkable polynomials, the F-, H- and M-triangle. \; The F-triangle is a refined face generating polynomial of the cluster complex, the H-triangle is a refined generating function of nonnesting partitions, and the M-triangle is a bivariate generating function of the Möbius function in the noncrossing partition lattice. \; He observed that these three polynomials are related by an invertible substitution of variables. \; These observations were proven uniformly by Athanasiadis and Thiel, respectively.  \;
In this talk, we explain how the F- and the H-triangle arise as refined versions of the f- and the h-polynomial of a polytope, and give a simple, combinatorial proof of Chapoton's relation in the context of v-associahedra. \; The relation with the M-triangle is much less clear. \; We conjecture a characterization of the northeast paths for which Chapoton's relation generalizes to this setting. \; Computational evidence suggests a close connection to the pureness of v-associahedra.  \;
This is based on joint work with Cesar Ceballos from TU Graz.


Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409

5/2717:00

Isabella Novik (University of Washington)



Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409

6/315:15

Martina Junke-Kubitzke (U Osnabrück)



Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409

6/1016:30

Isabel Hubard (UNAM)



Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409

6/1715:15

Aram Dermenjian (York University)



Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409

6/2415:15

Julian Pfeifle (UPC Barcelona)



Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409

7/115:15

Thomas Kahle (OvGU Magdeburg)



Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409

7/815:15

Laith Rastanawi (FU Berlin)



Where: Seminar Room @ Villa and Zoom:
https://sfsu.zoom.us/j/88391753769?pwd=OEpTVjBic2ZRZmw4UytIUmlOS3E0UT09
Meeting ID: 883 9175 3769
Passcode: 339409