{ "149657-21906898": { "datetime_modified":"20260922T115750", "datetime_start":"20260930T153000", "datetime_end":"20260930T165000", "has_end_time":1, "date_start":"2026-09-30", "date_end":"2026-09-30", "time_start":"15:30:00", "time_end":"16:50:00", "time_zone":"America\/Detroit", "event_title":"Algebraic Geometry Seminar: Crepant resolutions via stacks", "occurrence_title":"", "combined_title":"Algebraic Geometry Seminar: Crepant resolutions via stacks: Jeremy Usatine, Florida State University", "event_subtitle":"Jeremy Usatine, Florida State University", "event_type":"Workshop \/ Seminar", "event_type_id":"21", "description":"Consider an invariant that behaves nicely for smooth varieties, such as Euler number, Betti numbers, or Hodge numbers. Suppose we want a version of this invariant for singular varieties that sees interesting information about the singularities. I will discuss how this naturally leads to the notion of crepant resolutions of singularities. However, crepant resolutions (by varieties) are rare in practice. I will discuss joint work with M. Satriano in which we show that crepant resolutions actually exist in broad generality, as long as one is willing to consider algebraic stacks. Specifically, any variety with log-terminal singularities admits a crepant resolution by a smooth algebraic stack. As one consequence, in joint work with J. Huang and M. Satriano, we obtain a cohomological interpretation for Batyrev's stringy Hodge numbers. This talk will not assume familiarity with stacks.", "occurrence_notes":null, "guid":"149657-21906898@events.umich.edu", "permalink":"http:\/\/events.umich.edu\/event\/149657", "building_id":"1000166", "building_name":"East Hall", "campus_maps_id":"53", "room":"4096", "location_name":"East Hall", "has_livestream":0, "cost":"", "tags":["Mathematics"], "website":"", "sponsors":[ { "group_name":"Algebraic Geometry Seminar - Department of Mathematics", "group_id":"4880", "website":"" } ], "image_url":"", "styled_images":{ "event_thumb":"", "event_large":"", "event_large_2x":"", "event_large_lightbox":"", "group_thumb":"", "group_thumb_square":"", "group_large":"", "group_large_lightbox":"", "event_large_crop":"", "event_list":"", "event_list_2x":"", "event_grid":"", "event_grid_2x":"", "event_feature_large":"", "event_feature_thumb":"" }, "occurrence_count":1, "first_occurrence":21906898 } , "150891-21910382": { "datetime_modified":"20260904T215024", "datetime_start":"20261007T153000", "datetime_end":"20261007T170000", "has_end_time":1, "date_start":"2026-10-07", "date_end":"2026-10-07", "time_start":"15:30:00", "time_end":"17:00:00", "time_zone":"America\/Detroit", "event_title":"Algebraic Geometry Seminar: Proof of Miyanishi's conjecture on endomorphisms of varieties", "occurrence_title":"", "combined_title":"Algebraic Geometry Seminar: Proof of Miyanishi's conjecture on endomorphisms of varieties: Supravat Sarkar (Princeton University)", "event_subtitle":"Supravat Sarkar (Princeton University)", "event_type":"Workshop \/ Seminar", "event_type_id":"21", "description":"If X is a quasi-projective variety over a field k and f is a birational endomorphism of X that is injective outside a closed subset of codimension at least 2, we prove that f is an automorphism. This generalizes an old theorem of Ax and proves a conjecture of Miyanishi from 2005. A key step in our proof is a finiteness result on class groups, which is of interest in its own right.", "occurrence_notes":null, "guid":"150891-21910382@events.umich.edu", "permalink":"http:\/\/events.umich.edu\/event\/150891", "building_id":"1000166", "building_name":"East Hall", "campus_maps_id":"53", "room":"4096", "location_name":"East Hall", "has_livestream":0, "cost":"", "tags":["Mathematics"], "website":"", "sponsors":[ { "group_name":"Algebraic Geometry Seminar - Department of Mathematics", "group_id":"4880", "website":"" } ], "image_url":"", "styled_images":{ "event_thumb":"", "event_large":"", "event_large_2x":"", "event_large_lightbox":"", "group_thumb":"", "group_thumb_square":"", "group_large":"", "group_large_lightbox":"", "event_large_crop":"", "event_list":"", "event_list_2x":"", "event_grid":"", "event_grid_2x":"", "event_feature_large":"", "event_feature_thumb":"" }, "occurrence_count":1, "first_occurrence":21910382 } , "150254-21908471": { "datetime_modified":"20260814T013551", "datetime_start":"20261014T153000", "datetime_end":"20261014T170000", "has_end_time":1, "date_start":"2026-10-14", "date_end":"2026-10-14", "time_start":"15:30:00", "time_end":"17:00:00", "time_zone":"America\/Detroit", "event_title":"Algebraic Geometry Seminar: TBA", "occurrence_title":"", "combined_title":"Algebraic Geometry Seminar: TBA: Elden Elmanto (University of Toronto)", "event_subtitle":"Elden Elmanto (University of Toronto)", "event_type":"Workshop \/ Seminar", "event_type_id":"21", "description":"TBA", "occurrence_notes":null, "guid":"150254-21908471@events.umich.edu", "permalink":"http:\/\/events.umich.edu\/event\/150254", "building_id":"1000166", "building_name":"East Hall", "campus_maps_id":"53", "room":"4096", "location_name":"East Hall", "has_livestream":0, "cost":"", "tags":["Mathematics"], "website":"", "sponsors":[ { "group_name":"Algebraic Geometry Seminar - 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