1 ∞-Operads 4 1.1 Basic Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Fibrations of ∞-Operads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3 Algebra Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.4 Cartesian Monoidal Structures . . . . . . . . . . ....

This note presents a partially new proof of Farkas’ lemma, based on no other tools than elementary linear algebra (matrixand vector calculus). No properties of the real numbers other than those shared by the rational numbers are used. The general approach is the same as in the paper by A. Dax from 1997 (SIAM Review, 39(3):503-507), but instead of using an active set method for proving the exist...

1 Monoidal ∞-Categories 4 1.1 Monoidal Structures and Algebra Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Cartesian Monoidal Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.3 Subcategories of Monoidal ∞-Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.4 Free Algebras . . . . . . . . . . . . . . . . . . ....

Since the work of Mikhail Kapranov in [Kap], it is known that the shifted tangent complex TX r ́1s of a smooth algebraic variety X is endowed with a weak Lie structure. Moreover any complex of quasi-coherent sheaves on X is endowed with a weak Lie action of this tangent Lie algebra. We will generalize this result to (finite enough) derived Artin stacks, without any smoothness assumption. This in...

1 ∞-Operads 4 1.1 Basic Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Fibrations of ∞-Operads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3 Algebra Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.4 Cartesian Monoidal Structures . . . . . . . . . . ....

J. P. MAY I will give a philosophical overview of some joint work with Igor Kriz (in algebra), with Tony Elmendorf and Kriz (in topology), and with John Greenlees (in equivariant topology). I will begin with a description of some foundational issues before saying anything about the applications. This is not the best way to motivate people, but I must explain the issues involved in order to desc...

1 Monoidal ∞-Categories 4 1.1 Monoidal Structures and Algebra Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Cartesian Monoidal Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.3 Subcategories of Monoidal ∞-Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.4 Free Algebras . . . . . . . . . . . . . . . . . . ....