Band sum
Template:Short description In geometric topology, a band sum of two n-dimensional knots K1 and K2 along an (n + 1)-dimensional 1-handle h called a band is an n-dimensional knot K such that:
- There is an (n + 1)-dimensional 1-handle h connected to (K1, K2) embedded in Sn+2.
- There are points <math>p_1\in K_1</math> and <math>p_2\in K_2</math> such that <math>h</math> is attached to <math>K_1\sqcup K_2</math> along <math>p_1\sqcup p_2</math>.
K is the n-dimensional knot obtained by this surgery.
A band sum is thus a generalization of the usual connected sum of knots.