Formality of the Little $N$-disks Operad

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Formality of the Little $N$-disks Operad is written by Pascal Lambrechts and published by American Mathematical Soc.. It's available with International Standard Book Number or ISBN identification 0821892126 (ISBN 10) and 9780821892121 (ISBN 13).

The little -disks operad, , along with its variants, is an important tool in homotopy theory. It is defined in terms of configurations of disjoint -dimensional disks inside the standard unit disk in and it was initially conceived for detecting and understanding -fold loop spaces. Its many uses now stretch across a variety of disciplines including topology, algebra, and mathematical physics. In this paper, the authors develop the details of Kontsevich's proof of the formality of little -disks operad over the field of real numbers. More precisely, one can consider the singular chains on as well as the singular homology of . These two objects are operads in the category of chain complexes. The formality then states that there is a zig-zag of quasi-isomorphisms connecting these two operads. The formality also in some sense holds in the category of commutative differential graded algebras. The authors additionally prove a relative version of the formality for the inclusion of the little -disks operad in the little -disks operad when .