Cancellation Results for 2-Complexes and 4-Manifolds and Some Applications

This is a survey chapter. The idea is to summarize some recent work which illustrates in one way or another the connection between topology in dimension 2 and the study of 4-dimensional manifolds. There are almost no new results and no result is proved completely in the paper. Instead, in each section we collect together some related statements and motivation, and give a sketch of some typical or important steps in the proofs. A Cancellation …