Bounding singular surfaces of general type
نویسندگان
چکیده
We provide simpler proofs of several boundedness theorems, contained in in articles [2], [3], for log surfaces of general type with semi log canonical singularities. At the same time, we make these proofs e ective, with explicit upper bounds.
منابع مشابه
Computations with Tight Bounding Volumes for General Parametric Surfaces
Methods for computing tight bounding volumes for general parametric surfaces, for testing if two bounding volumes intersect and for computing inclusions for the intersection of two bounding volumes are discussed. These methods together with interval arithmetic are the basis for a robust algorithm for computing inclusions for all parts of the intersection curve of two general parametric surfaces.
متن کاملGeneralized Helices and Singular Points
In this paper, we define X-slant helix in Euclidean 3-space and we obtain helix, slant helix, clad and g-clad helix as special case of the X-slant helix. Then we study Darboux, tangential darboux developable surfaces and their singular points. Especially we show that the striction lines of these surfaces are singular locus of the surfaces.
متن کاملReliable Ray Tracing by Linear Interval Estimations
Recently Bühler has introduced a new type of bounding volume for parametric surfaces. These bounding volumes, which Bühler calls Linear Interval Estimations (LIEs), are parametrized with the same parametrization as the surfaces they bound. We report on the application of LIEs to the ray tracing of Bezier surfaces. The general nonlinear ray–surface intersection problem is replaced with a linear ...
متن کاملApproximating the Distributions of Singular Quadratic Expressions and their Ratios
Noncentral indefinite quadratic expressions in possibly non- singular normal vectors are represented in terms of the difference of two positive definite quadratic forms and an independently distributed linear combination of standard normal random variables. This result also ap- plies to quadratic forms in singular normal vectors for which no general representation is currently available. The ...
متن کاملIntersecting general parametric surfaces using bounding volumes
This paper describes a robust algorithm for computing all parts of the intersection curve of two general parametric surfaces. The algorithm follows a divide-and-conquer approach. Surfaces (and parts of them) are enclosed by tight parallel epipeds and axis aligned bounding boxes. If two bounding volumes intersect, one surface is split into two patches. This step is repeated recur-sively for both...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1995