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        "event_title":"Periodic pipe dreams and matrix positroid varieties",
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        "combined_title":"Periodic pipe dreams and matrix positroid varieties: Allen Knutson (Cornell University)",
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        "description":"Fan, Guo, Su and our own Rui Xiong introduced \"periodic pipe dreams\" to compute fundamental  classes of positroid varieties, as classes on Grassmannians. Their formula is too beautiful to live only in a quotient ring. I'll explain some subtleties in interpreting it geometrically upstairs in the polynomial ring, and extend it to compute classes of other projected Richardson varieties. As in the work of Fan, Guo, Su and Xiong, we will also discuss CSM classes of the related open varieties.  This work is joint with Paul Zinn-Justin.",
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        "building_name":"East Hall",
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        "room":"4088",
        "location_name":"East Hall",
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        "tags":["Mathematics"],
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                "group_name":"Combinatorics Seminar - Department of Mathematics",
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        "datetime_modified":"20260914T101215",
        "datetime_start":"20261106T150000",
        "datetime_end":"20261106T154500",
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        "time_end":"15:45:00",
        "time_zone":"America\/Detroit",
        "event_title":"Sky Tonight",
        "occurrence_title":"",
        "combined_title":"Sky Tonight",
        "event_subtitle":"",
        "event_type":"Film Screening",
        "event_type_id":"11",
        "description":"A live presentation on what to find in the sky tonight and for the coming few weeks. This presentation includes how to find the cardinal directions with the North Star, current and upcoming constellations, visible planets, a few deep sky objects depending on the season, and other interesting astronomical visualizations. If you want to be able to look up from your own backyard and know what to look for, this is the show for you.",
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        "building_name":"Museum of Natural History",
        "campus_maps_id":"646",
        "room":"Planetarium & Dome Theater",
        "location_name":"Museum of Natural History",
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        "cost":"Tickets are $9 and are available in the museum store on the day of the show.",
        "tags":["Astronomy","Children","Family","Film","Museum","museums","natural history museum","Natural Sciences","Planetarium","Prospective Undergraduate Students","Science","Space","Undergraduate"],
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