In Topology, Mathematicians study an idealized version of knots. A topological knot is made in a rope with no ends -- i.e. a circle. An as yet unsolved problem in Knot Theory is to determine a mathematical invariant (something like a number, or a polynomial, that one can compute) which distinguishes figures that are truly knotted from unknotted loops that only appear to be knotted.
Can you determine if the knot in the image above is a knot or not?