Notes for AKT-090910-2/0:15:44

Definitions of positive and negative crossings and the writhe of an oriented knot diagram.

Positive crossing [math]\displaystyle{ :\overcrossing }[/math]

Negative crossing [math]\displaystyle{ :\undercrossing }[/math]

The writhe of an oriented knot diagram is the sum of the signs of all the crossings in the diagram.