Ruiz Sancho, Jesús M.Rojo Carulli, Juan Ángel2023-06-192023-06-192013-07https://hdl.handle.net/20.500.14352/37089In this paper we deal with aproximation and homotopy of continuous and proper continuous mappings whose target is a manifold with boundary. That requires a careful examination of the construction of collars in manifolds with boundary, which will enable us to find diferentiable pseudoretracts onto the boundary. On the other hand, to use the aproximation and homotopy results known for boundaryless manifols, we will embed any given manifold with boundary into a boundaryless manifold of the same dimension in the same ambient space.spabachelor thesisopen access515.14Topología algebraicaMatemáticas (Matemáticas)Topología12 Matemáticas1210 Topología