A Geometric Interpretation of the Normal Closure of the Braid Group $B_n$ in the braid group of the torus $B_n(T)$

Liming Pang

Combining the results by Birman and Goldberg, it was proved the normal closure of the pure braid group of the disk $P_n(D)$ in the pure braid group of the torus $P_n(T)$ is the com…