“Given the front and rear wheel tracks, can one always tell which way the bicycle went?” This is one of the questions to be addressed by Penn State’s Sergei Tabachnikov in “Flavors of ‘Bicycle Mathematics,’” scheduled for 5:15 p.m. Sept. 11 in the Sciences Lecture Hall. The program continues with Flatland: The Movie — and both the talk and the film are free and open to the public.

The public also is invited to a barbecue after the talk and the film. The cost is $10, with no reservations required.

The lecture, film and BBQ are part of the Sept. 11-13 international conference, Algebra and Topology in Interaction, honoring UC Davis Professor Dmitry Fuchs for his accomplishments — and his 70th birthday. More information.

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THE SEARCH IS ON: Shields Library is offering summer instruction in search skills for biological and agricultural researchers. Registration and more information.

HUMPHREY FELLOWS GLOBAL FORUM: Talks by 14 fellows from around the world. 10 a.m.-5 p.m. Sept. 2, International House, 10 College Place, Davis.

WEED SCIENCE SCHOOL: Sept. 21-23, Bowley (Plant) Science Teaching Center. $550 before Sept. 4 ($600 after that date). Sponsored by the Weed Research Information Center. Registration and more information.

FRESH-CUT PRODUCTS WORKSHOP: Sept. 22-24, Buehler Alumni and Visitors Center. $1,050. Sponsored by the Postharvest Technology Research and Information Center. Registration and more information.