Stacks and categories in geometry, topology, and algebra : CATS4 conference, higher categorical structures and their interactions with algebraic geometry, algebraic topology and algebra, July 2-7, 2012, CIRM, Luminy, France - Pantev, Tony, 1963-; Simpson, Carlos, 1962-; Toën, Bertrand, 1973-; Vaquié, Michel; Vezzosi, Gabriele, 1966- (American Mathematical Society, 2015)