Hello, The next Banach spaces webinar is on Friday February 12 at 9AM Central time. Please join us at https://unt.zoom.us/j/83807914306 Speaker: Mikael de la Salle (ENS Lyon) Title: On a duality between Banach spaces and operators Abstract: Most classical local properties of a Banach spaces (for example type or cotype, UMD) are defined in terms of the boundedness of vector-valued operators between Lp spaces or their subspaces. It was in fact proved by Hernandez in the early 1980s that this is the case of any property that is stable by Lp direct sums and finite representability. His result can be seen as one direction of a bipolar theorem for a non-linear duality between Banach spaces and operators. I will present the other direction and describe the bipolar of any class of operators for this duality. The talk will be based on my recent preprint arxiv:2101.07666. For more information about the past and future talks, and videos please visit the webinar website http://www.math.unt.edu/~bunyamin/banach Thank you, and best regards, Bunyamin Sari