seminars:colloquium
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seminars:colloquium [2025/10/02 13:55] adrian |
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| ====== Colloquium ====== | ====== Colloquium ====== | ||
| - | Unless stated otherwise, colloquia are scheduled for Thursdays 4:15-5:15pm in WH-100E with refreshments served from 4:00-4:15 pm in WH-102. | + | Unless stated otherwise, colloquia are scheduled for Thursdays 4:00-5:00pm in WH-100E with refreshments served from 3:45-4:00 pm in WH-102. |
| Organizers: [[people:dobbins:start]], [[people:kargin:start|Vladislav Kargin]], [[people:malkiewich:start]], | Organizers: [[people:dobbins:start]], [[people:kargin:start|Vladislav Kargin]], [[people:malkiewich:start]], | ||
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| ==== Fall 2025 ==== | ==== Fall 2025 ==== | ||
| - | **Thursday Nov 6 4:00-5:00pm, WH-100E**\\ //Speaker//: ** [[ https://www.gc.cuny.edu/people/andrew-obus | Andrew Obus]] ** (CUNY) \\ //Topic//: **//TBA//** \\ | + | **Thursday Nov 6 4:00-5:00pm, WH-100E**\\ //Speaker//: ** [[ https://blogs.baruch.cuny.edu/aobus/ | Andrew Obus]] ** (CUNY) \\ //Topic//: **//The lifting problem for covers of curves, particularly its group-theoretical aspects//** \\ |
| <WRAP box 90%> | <WRAP box 90%> | ||
| **//Abstract//**: | **//Abstract//**: | ||
| - | TBA\\ | + | Whenever a mathematical object is given in |
| + | characteristic p, one can ask whether it is the reduction, in some | ||
| + | sense, of an analogous structure in characteristic zero. If so, the | ||
| + | structure in characteristic zero is called a "lift" of the structure | ||
| + | in characteristic p. The most famous example is Hensel's Lemma about | ||
| + | lifting solutions of polynomials in Z/p to solutions in the p-adic | ||
| + | integers Z_p. | ||
| + | |||
| + | The “lifting problem” we consider is more geometric: given a smooth curve X in | ||
| + | characteristic p with an action of a finite group G, is there a curve | ||
| + | in characteristic zero with G-action that reduces to X? Unsurprisingly, the answer is related to the group theory of G (for instance, if p does not divide |G| or if G is cyclic, then the curve with the G-action always lifts, but if G has an abelian, non-cyclic, non-p-subgroup that fixes a point on X, then the curve does not lift with the action). After giving an introduction to the lifting problem and some examples, we will discuss well-established ways that the problem interacts with group theory, as well as more recent advances relating the problem to representation theory.\\ | ||
| </WRAP> | </WRAP> | ||
seminars/colloquium.1759427701.txt · Last modified: 2025/10/02 13:55 by adrian