Formality of the Little N-Disks Operad
Author: Pascal Lambrechts
Publisher:
Published: 2014-09-11
Total Pages: 130
ISBN-13: 9781470416690
DOWNLOAD EBOOKThe little $N$-disks operad $\mathcal B$ 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 $\mathbb{R} DEGREESN$ and it was initially conceived for detecting and understanding $N$-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 $N$-disks operad over the field of real numbers. More precisely one can consider the singular chains $\operatorname{C}_*(\mathcal B; \mathbb{R})$ on $\mathcal B$ as well as the singular homology $\operatorname{H}_*(\mathcal B; \mathbb{R})$ of $\mathcal B$. 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 $m$-disks operad in the little $N$-disks operad when $N\ge