Knot Theory 7: Linking Number 

The man deserves a raise whatever his salary

This is a great video to explain the concept of the linking number from different perspectives.

To easily find if the linking number is greater than 0 you have to find out if it's odd or even. So basically count how many overs and unders you have. Start with a point on a line in the system and then follow that point all the way through until you're back where you started and if the number of overs is even or odd will tell you about the relationship of the two loops to some degree. I don't feel like thinking this all the way though so I guess this would just be a starting point to figuring out how to use odds and evens to find out some of the qualities of your system you're looking for in terms of linking numbers

How did Gauss come up with that complicated integral? Any intuition?