Milnor Fiber Boundary of a Non-isolated Surface Singularity

In the study of algebraic/analytic varieties a key aspect is the description of the invariants of their singularities. This book targets the challenging non-isolated case. Let f be a complex analytic hypersurface germ in three variables whose zero set has a 1-dimensional singular locus. We develop an explicit procedure and algorithm that describe the boundary M of the Milnor fiber of f as an oriented plumbed 3-manifold. This method also provides the characteristic polynomial of the algebraic monodromy. We then determine the multiplicity system of the open book decomposition of M cut out by the argument of g for any complex analytic germ g such that the pair (f,g) is an ICIS. Moreover, the horizontal and vertical monodromies of the transversal type singularities associated with the singular locus of f and of the ICIS (f,g) are also described. The theory is supported by a substantial amount of examples, including homogeneous and composed singularities and suspensions. The properties peculiar to M are also emphasized.

Presents a new approach in the study of non-isolated hypersurface singularities The first book about non-isolated hypersurface singularities Conceptual and comprehensive description of invariants of non-isolated singularities Key connections between singularity theory and low-dimensional topology Numerous explicit examples for plumbing representation of the boundary of the Milnor fiber Numerous explicit examples for the Jordan block structure of different monodromy operators

Inhalt

1 Introduction.- 2 The topology of a hypersurface germ f in three variables Milnor fiber.- 3 The topology of a pair (f ; g).- 4 Plumbing graphs and oriented plumbed 3-manifolds.- 5 Cyclic coverings of graphs.- 6 The graph GC of a pair (f ; g). The definition.- 7 The graph GC . Properties.- 8 Examples. Homogeneous singularities.- 9 Examples. Families associated with plane curve singularities.- 10 The Main Algorithm.- 11 Proof of the Main Algorithm.- 12The Collapsing Main Algorithm.- 13 Vertical/horizontal monodromies.- 14 The algebraic monodromy of H1(¶ F). Starting point.- 15 The ranks of H1(¶ F) and H1(¶ F n V g) via plumbing.- 16 The characteristic polynomial of ¶ F via P# and P#.- 18 The mixed Hodge structure of H1(¶ F).- 19 Homogeneous singularities.- 20 Cylinders of plane curve singularities: f = f 0(x ; y).- 21 Germs f of type z f 0(x ; y).- 22 The T¤;¤;¤family.- 23 Germs f of type f (x a y b ; z). Suspensions.- 24 Peculiar structures on ¶ F. Topics for future research.- 25 List of examples.- 26 List of notations