A. Joyal, Ross Street, An introduction to Tannaka duality and quantum groups, Category theory (Como, 1990), 413—492, Lecture Notes in Math.
An alternative bijective proof, given by Aigner and Ziegler and credited by them to André Joyal, involves a bijection between, on the one hand, n-node trees with two designated nodes (that may be the same as each other), and on the other hand, n-node directed pseudoforests.
Infinity categories (in the form of Joyal's quasi-categories) are a convenient framework to do homotopy theory in abstract settings.
Kripke semantics (also known as relational semantics or frame semantics, and often confused with possible world semantics) is a formal semantics for non-classical logic systems created in the late 1950s and early 1960s by Saul Kripke and André Joyal.
André Joyal used this fact to provide a bijective proof of Cayley's formula, that the number of undirected trees on n nodes is nn − 2, by finding a bijection between maximal directed pseudoforests and undirected trees with two distinguished nodes.
André Previn | André Breton | Andre Agassi | André Malraux | André Derain | Victor André Cornil | Carl Andre | Andre Ward | Fabrizio De André | André the Giant | André Heller | André Gide | André-Gaston Prételat | André | Andre Norton | André Masséna | André Guignard | André Franquin | Andre Begemann | Peter Andre | Andre Williams | Andre Ware | André Leon Talley | André Le Nôtre | André Glucksmann | André Charlot | André Sogliuzzo | André Marie Constant Duméril | André-Jacques Garnerin | André Bauer |