Polynomic rethink

Ross Street – 22 May 2019

This talk still runs with the idea that polynomials can be considered as certain spans of spans. Polynomials are now defined in bicategories equipped with a calibration, which is a class of morphisms called neat. The bicategory is polynomic as in the last talk when the groupoid fibrations are the neat morphisms for a calibration. Tabulations are used to produce examples of calibrations. This is a fairly major revision of the topic (although the calibration and tabulation ideas were in a dismissed version from January 2019) and allows for examples other than bicategories of spans.