We characterize C embedded hypersurfaces of R as the only locally closed sets with continuously varying flat tangent cones whose measuretheoretic-multiplicity is at most m < 3/2. It follows then that any (topological) hypersurface which has flat tangent cones and is supported everywhere by balls of uniform radius is C. In the real analytic case the same conclusion holds under the weakened hypot...

We propose a new model for representing a hypersurface describing a scalar field in any dimension at different levels of detail. The model is based on a decomposition of the domain into a hierarchy of simplicial complexes. We present a data structure for encoding such model as well as an algorithm for building a multiresolution representation of a hypersurface based on a decreasing sequence of ...

Kähler’s paper Über die Verzweigung einer algebraischen Funktion zweier Veränderlichen in der Umgebung einer singulären Stelle” offered a more perceptual view of the link of a complex plane curve singularity than that provided shortly before by Brauner. Kähler’s innovation of using a “square sphere” became standard in the toolkit of later researchers on singularities. We describe his contributi...

We derive the equations of Gauss and Weingarten for a non-degenerate hypersurface of a semi-Riemannian manifold admitting a semi-symmetric metric connection, and give some corollaries of these equations. In addition, we obtain the equations of Gauss curvature and Codazzi-Mainardi for this non-degenerate hypersurface and give a relation between the Ricci and the scalar curvatures of a semi-Riema...

A monoid hypersurface is an irreducible hypersurface of degree d which has a singular point of multiplicity d−1. Any monoid hypersurface admits a rational parameterization, hence is of potential interest in computer aided geometric design. We study properties of monoids in general and of monoid surfaces in particular. The main results include a description of the possible real forms of the sing...

An analytic hypersurface of M is a subset V ⊂ M such that for each point x ∈ V there exists an open set Ux ⊂ M containing x and a holomorphic function fx defined on Ux such that V ⊂ Ux is the zero-set of fx. Such an fx is called a local defining function for V near x. The quotient of any two local defining functions around x is a non-vanishing holomorphic function around x. An analytic hypersur...

We use bounds of mixed character sums modulo a square-free integer q of a special structure to estimate the density of integer points on the hypersurface f1(x1) + . . . + fn(xn) = ax k1 1 . . . x kn n for some polynomials fi ∈ Z[X] and nonzero integers a and ki, i = 1, . . . , n. In the case of f1(X) = . . . = fn(X) = X 2 and k1 = . . . = kn = 1 the above hypersurface is known as the Markoff-Hu...

Let M be an orientable connected and compact real hypersurface of the complex space form C(n+1)/2. If the mean curvature α and the function f = g(Aξ, ξ) of hypersurface M satisfy the inequalityn2α2 ≤ (n2 − 1)δ + f 2, where ξ is the characteristic vector field,A is the shape operator and (n− 1)δ is the infimum of the Ricci curvatures of hypersurface M , then it is shown that α is a constant and ...

Let M^2n be a hoph hypersurfaces with parallel ricci operator and tangent to structure vector field in Sasakian space form. First, we show that structures and properties of hypersurfaces and hoph hypersurfaces in Sasakian space form. Then we study the structure of hypersurfaces and hoph hypersurfaces with a parallel ricci tensor structure and show that there are two cases. In the first case, th...