The empty set, I presume. As a computer science student, I have to juggle O, o, ...

		dvdkon 11 months ago \| parent \| context \| favorite \| on: Tips for mathematical handwriting (2007) The empty set, I presume. As a computer science student, I have to juggle O, o, 0, and ∅. (capital/lowercase letter, zero, empty set. Fun!