PROPs and their variants are extremely general and powerful machines that encode operations with multiple inputs and multiple outputs. In this respect PROPs can be viewed as generalizations of operads that would allow only a single output. Variants of PROPs are important in seve…
Operads and chain rules for the calculus of functors
by Ching, Michael, Arone, Greg
fromAstérisque
The Grothendieck-Teichmüller group was defined by Drinfeld in quantum group theory with insights coming from the Grothendieck program in Galois theory. The ultimate goal of this book is to explain that this group has a topological interpretation as a group of homotopy automorphi…
The algebraic theory and its topological background -- The applications of (rational) homotopy theory methods
The little N-disks operad, B, along with its variants, is an important tool in homotopy theory. It is defined in terms of configurations of disjoint N-dimensional disks inside the standard unit disk in R [superscript]N and it was initially conceived for detecting and understandi…