The Intrinsic Geometry of Dynamic Observations

Author(s):  
Arthur J. Krener
Keyword(s):  
2021 ◽  
Vol 27 (2) ◽  
Author(s):  
Graham A. Niblo ◽  
Nick Wright ◽  
Jiawen Zhang

AbstractThis paper establishes a new combinatorial framework for the study of coarse median spaces, bridging the worlds of asymptotic geometry, algebra and combinatorics. We introduce a simple and entirely algebraic notion of coarse median algebra which simultaneously generalises the concepts of bounded geometry coarse median spaces and classical discrete median algebras. We study the coarse median universe from the perspective of intervals, with a particular focus on cardinality as a proxy for distance. In particular we prove that the metric on a quasi-geodesic coarse median space of bounded geometry can be constructed up to quasi-isometry using only the coarse median operator. Finally we develop a concept of rank for coarse median algebras in terms of the geometry of intervals and show that the notion of finite rank coarse median algebra provides a natural higher dimensional analogue of Gromov’s concept of $$\delta $$ δ -hyperbolicity.


1994 ◽  
Vol 166 (3) ◽  
pp. 261-273 ◽  
Author(s):  
Lewis D. Griffin

2003 ◽  
Vol 6 (3) ◽  
pp. 291-299
Author(s):  
Carlo Cattani ◽  
Ettore Laserra

2014 ◽  
Vol 214 (1) ◽  
pp. 99-142 ◽  
Author(s):  
Pekka Koskela ◽  
Nageswari Shanmugalingam ◽  
Yuan Zhou

Author(s):  
Shahriar Tavakkoli ◽  
Sanjay G. Dhande

Abstract The present paper outlines a method of shape synthesis using intrinsic geometry to be used for two-dimensional shape optimization problems. It is observed that the shape of a curve can be defined in terms of intrinsic parameters such as the curvature as a function of the arc length. The method of shape synthesis, proposed here, consists of selecting a shape model, defining a set of shape design variables and then evaluating Cartesian coordinates of a curve. A shape model is conceived as a set of continuous piecewise linear segments of the curvature; each segment defined as a function of the arc length. The shape design variables are the values of curvature and/or arc lengths at some of the end-points of the linear segments. The proposed method of shape synthesis and optimization is general in nature. It has been shown how the proposed method can be used to find the optimal shape of a planar Variable Geometry Truss (VGT) manipulator for a pre-specified position and orientation of the end-effector. In conclusion, it can be said that the proposed approach requires fewer design variables as compared to the methods where shape is represented using spline-like functions.


1979 ◽  
Vol 74 (6) ◽  
pp. 381-383 ◽  
Author(s):  
Harry I. Ringermacher
Keyword(s):  

1999 ◽  
Vol 14 (29) ◽  
pp. 4549-4574 ◽  
Author(s):  
C. R. GATTRINGER ◽  
S. JAIMUNGAL ◽  
G. W. SEMENOFF

We construct an algebraic representation of the geometrical objects (loop and surface variables) dual to the spins in 2 and 3D Ising models. This algebraic calculus is simpler than dealing with the geometrical objects, in particular when analyzing geometry factors and counting problems. For the 2D case we give the corrected loop expansion of the free energy and the radius of convergence for this series. For the 3D case we give a simple derivation of the geometry factor which prevents overcounting of surfaces in the intrinsic geometry representation of the partition function, and find a classification of the surfaces to be summed over. For 2 and 3D we derive a compact formula for 2n-point functions in loop (surface) representation.


2020 ◽  
Vol 55 ◽  
pp. 101576 ◽  
Author(s):  
Gi-Ren Liu ◽  
Yu-Lun Lo ◽  
John Malik ◽  
Yuan-Chung Sheu ◽  
Hau-Tieng Wu

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