In mathematics , the differential geometry of surfaces deals with the differential geometry of smooth surfaces with various additional structures, most often, a Riemannian metric. Surfaces have been extensively studied from various perspectives: extrinsically , relating to their embedding in Euclidean space and intrinsically , reflecting their properties determined solely by the distance within the surface as measured along curves on the surface. One of the fundamental concepts investigated is the Gaussian curvature , first studied in depth by Carl Friedrich Gauss ,  who showed that curvature was an intrinsic property of a surface, independent of its isometric embedding in Euclidean space. Surfaces naturally arise as graphs of functions of a pair of variables , and sometimes appear in parametric form or as loci associated to space curves. An important role in their study has been played by Lie groups in the spirit of the Erlangen program , namely the symmetry groups of the Euclidean plane , the sphere and the hyperbolic plane. These Lie groups can be used to describe surfaces of constant Gaussian curvature; they also provide an essential ingredient in the modern approach to intrinsic differential geometry through connections.
Stephan M. Weingarten
Briefly Noted Book Reviews | The New Yorker
NLRB v. Weingarten, Inc. It held that employees in unionized workplaces have the right under the National Labor Relations Act to the presence of a union steward during any management inquiry that the employee reasonably believes may result in discipline. In , J. Weingarten operated a chain of food outlets.
Subscribe to RSS
Sutherland has been a leader in Mechanical Presses for over 70 years. We are constantly pushing the industry forward with innovations in manufacturing, materials, and controls. We offer a full range of Mechanical Presses up to ton capacities, with gap frames, straight sides, single and double point configurations to serve a wide variety of applications.
Thread Whirling is a form of the Thread Milling process with the exception that the cutters are mounted on the inside of a Cutting Ring or Cutter Holder rather than the outside of a milling tool. Recommended Parameters for Thread Whirling. The process is usually performed in a single pass from stock diameter which maintains constant material support. It eliminates special support devices and expensive startup development costs.