History and Motivation
Historically, elliptic cohomology arose from the study of elliptic genera. It is known by Atiyah and Hirzebruch that if acts smoothly and non-trivially on a spin manifold, then the index of the Dirac operator vanishes. In 1983, Witten conjectured that in this situation the equivariant index of a certain twisted Dirac operator is at least constant. This led to certain other problems concerning -actions on manifolds, which could be solved by Ochanine by the introduction of elliptic genera. These got in turn by Witten related to (conjectural) index theory on free loop spaces. Elliptic cohomology, invented in its original form by Landweber, Stong and Ravenel in the late 1980s, was introduced to clarify certain issues with elliptic genera and provide a context for (conjectural) index theory of families of differential operators on free loop spaces. In some sense it can be seen as an approximation to the K-theory of the free loop space.
Read more about this topic: Elliptic Cohomology
Famous quotes containing the words history and, history and/or motivation:
“History and experience tell us that moral progress comes not in comfortable and complacent times, but out of trial and confusion.”
—Gerald R. Ford (b. 1913)
“Let it suffice that in the light of these two facts, namely, that the mind is One, and that nature is its correlative, history is to be read and written.”
—Ralph Waldo Emerson (1803–1882)
“Self-determination has to mean that the leader is your individual gut, and heart, and mind or we’re talking about power, again, and its rather well-known impurities. Who is really going to care whether you live or die and who is going to know the most intimate motivation for your laughter and your tears is the only person to be trusted to speak for you and to decide what you will or will not do.”
—June Jordan (b. 1939)