Engel structures April 17 to April 21, 2017 American Institute of Mathematics, San Jose, CA Organizers: Yakov Eliashberg, Dieter Kotschick, Emmy Murphy, and Thomas Vogel Description: This workshop, sponsored by AIM and the NSF, will be devoted to the emerging theory of Engel structures on four-manifolds, especially questions of rigidity versus flexibility, and its (potential) connections with contact topology, dynamics, and four-dimensional differential topology and gauge theory. Deadline: November 1, 2016 Details: http://aimath.org/workshops/upcoming/engelstr