Series:

Memoirs of the American Mathematical Society

3 total works

Cover of Medial/Skeletal Linking Structures for Multi-Region Configurations
The authors consider a generic configuration of regions, consisting of a collection of distinct compact regions $\{ \Omega_i\}$ in $\mathbb{R}^{n+1}$ which may be either regions with smooth boundaries disjoint from the others or regions which meet on their piecewise smooth boundaries $\mathcal{B}_i$ in a generic way. They introduce a skeletal linking structure for the collection of regions which simultaneously captures the regions' individual shapes and geometric properties as well as the ``positional geometry'' of the collection. The linking structure extends in a minimal way the individual ``skeletal structures'' on each of the regions. This allows the authors to significantly extend the mathematical methods introduced for single regions to the configuration of regions.

Cover of The Unfolding and Determinacy Theorems for Subgroups of A and K

Cover of Higher Multiplicities and Almost Free Divisors and Complete Intersections
In this book, the author considers a general class of nonisolated hypersurface and complete intersection singularities called 'almost free divisors and complete intersections', which simultaneously extend both the free divisors introduced by K. Saito and the isolated hypersurface and complete intersection singularities. They also include discriminants of mappings, bifurcation sets, and certain types of arrangements of hyperplanes, such as Coxeter arrangements and generic arrangements. Topological properties of these singularities are studied via a 'singular Milnor fibration' which has the same homotopy properties as the Milnor fibration for isolated singularities.The associated 'singular Milnor number' can be computed as the length of a determinantal module using a Bezout-type theorem. This allows one to define and compute higher multiplicities along the lines of Teissier's $\mu ^*$-constants. These are applied to deduce topological properties of singularities in a number of situations including: complements of hyperplane arrangements, various nonisolated complete intersections, nonlinear arrangements of hypersurfaces, functions on discriminants, singularities defined by compositions of functions, and bifurcation sets. It treats nonisolated and isolated singularities together. It uses the singular Milnor fibration with its simpler homotopy structure as an effective tool. It explicitly computes the singular Milnor number and higher multiplicities using a Bezout-type theorem for modules.