Timeline for Where does the definition of ($\infty$-)groupoid cardinality come from?
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 24, 2023 at 19:25 | vote | accept | Matthew Niemiro | ||
| Dec 23, 2023 at 16:27 | comment | added | Maxime Ramzi | You can phrase both "multiplicative along fiber sequences" and "additive on path components" with values in an arbitrary ring - or in fact just a rig, that is, you don't need additive inverses -, and the initial such function is the one with values in $\mathbb Q$ or $\mathbb Q_{\geq 0}$ if you don't like additive inverses | |
| Dec 23, 2023 at 15:09 | comment | added | Matthew Niemiro | Hi @MaximeRamzi, what exactly is the universality statement here? | |
| Dec 23, 2023 at 14:37 | comment | added | Matthew Niemiro | Thanks, so it is the unique multiplicative (in fiber sequences) extension of cardinality along FinSet \to \pi-finite spaces. | |
| Dec 23, 2023 at 12:17 | comment | added | Maxime Ramzi | In fact, beyond being unique, it is universal! | |
| Dec 23, 2023 at 1:12 | history | answered | Phil Tosteson | CC BY-SA 4.0 |