Timeline for Where does the $\hat A$ class get its name?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 14, 2019 at 21:26 | comment | added | Nick Addington | Nice finds Francois Ziegler -- thanks. | |
| May 12, 2019 at 2:31 | comment | added | Francois Ziegler | “The word “genus” is meant in the sense of my book (1956): A genus is a homomorphism of the Thom cobordism ring (...) into the complex numbers. Fundamental examples are the signature and the $\smash{\hat A}$-genus. The $\smash{\hat A}$-genus equals the arithmetic genus of an algebraic manifold, provided the first Chern class of the manifold vanishes. According to Atiyah and Singer it is the index of the Dirac operator on a compact Riemannian manifold with spin structure.” | |
| May 12, 2019 at 2:30 | comment | added | Francois Ziegler | For the record, $A$-genus is already in (1954). I wonder if it was to suggest the arithmetic genus Hirzebruch had once denoted $\Pi(V)$; for he writes in the first lines of (1992): | |
| May 11, 2019 at 4:13 | comment | added | Nick Addington | Do you have any guess what the L in $L$-genus stands for? | |
| May 11, 2019 at 4:12 | comment | added | Nick Addington | Very nice. I'd wondered if there was an $A$-genus as well as an $\hat A$-genus. | |
| May 11, 2019 at 4:12 | vote | accept | Nick Addington | ||
| May 10, 2019 at 22:05 | history | answered | user25309 | CC BY-SA 4.0 |