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.