Handlebody splittings of compact 3-manifolds with boundary.
The purpose of this paper is to relate several generalizations of the notion of the Heegaard splitting of a closed 3-manifold to compact, orientable 3-manifolds with nonempty boundary.
The purpose of this paper is to relate several generalizations of the notion of the Heegaard splitting of a closed 3-manifold to compact, orientable 3-manifolds with nonempty boundary.
Using Fox differential calculus, for any positive integer , we construct a map on the mapping class group of a surface of genus with one boundary component, such that, when restricted to an appropriate subgroup, it coincides with the Johnson-Morita homomorphism. This allows us to construct very easily a homomorphic extension to of the second and third Johnson-Morita homomorphisms.
We give a homotopy classification of nanophrases with at most four letters. It is an extension of the classification of nanophrases of length 2 with at most four letters, given by the author in a previous paper. As a corollary, we give a stable classification of ordered, pointed, oriented multi-component curves on surfaces with minimal crossing number less than or equal to 2 such that any equivalent curve has no simply closed curves in its components.