• On distributivity in higher algebra I: The universal property of bispans 

      Elmanto, Elden; Haugseng, Rune (Peer reviewed; Journal article, 2023)
      Structures where we have both a contravariant (pullback) and a covariant (pushforward) functoriality that satisfy base change can be encoded by functors out of (∞-)categories of spans (or correspondences). In this paper, ...