As we have seen in tangles and braids, though they are purely topological objects, they carry strong information to describe very abstract algebraic notions. We will see that the same is true for planar tangles and planar algebras, for which can be defined algebraically through operads.
Planar Tangles
As its name suggests, planar tangles are tangles that can be embedded into the plane.
Planar Tangle
A planar tangle
is a tangle