What is |? Hal Canary 2005-04-23 12:49:56-05:00 (CDT) https://halcanary.org/vv/2005/04/23/446/ #physics — Dirac, by way of the Feynman Lectures | is the identity matrix. SUM <i|i> = 1 while SUM |i><i| = I.
![[]](https://halcanary.org/images/ketbra.png)