A sharp Freiman type estimate for semisums in two and three dimensional Euclidean spaces

2021 ◽  
Vol 54 (1) ◽  
pp. 235-257
Author(s):  
Alessio Figalli ◽  
David Jerrison
2018 ◽  
Vol 10 (5) ◽  
pp. 28
Author(s):  
William Chen

In this paper we present a lemma and two theorems. These theoretical results will be used to test whether or not a given surface model can be developed. We then choose some examples to demonstrate how to perform these tests. All of these theories and examples are for general purposes, and are not restricted to any particular field. Although all examples are in three-dimensional space, it can be expanded to finite n-dimensional Euclidean spaces. The objective of this paper is to link the relationship between developable surfaces and information loss.


2000 ◽  
Vol 32 (3) ◽  
pp. 648-662 ◽  
Author(s):  
Yukinao Isokawa

We study Poisson-Voronoi tessellations in three-dimensional hyperbolic spaces, and give explicit expressions for mean surface area, mean perimeter length, and mean number of vertices of their cells. Furthermore we compare these mean characteristics with those for Poisson-Voronoi tessellations in three-dimensional Euclidean spaces. It is shown that, as the absolute value of the curvature of hyperbolic spaces increases from zero to infinity, these mean characteristics increase monotonically from those for the Euclidean case to infinity.


2015 ◽  
Vol 34 (3) ◽  
pp. 147 ◽  
Author(s):  
Luis Manuel Cruz-Orive ◽  
Ximo Gual-Arnau

The invariator is a method to generate a test line within an isotropically oriented plane through a fixed point, in such a way that the test line is effectively motion invariant in three dimensional space. Generalizations exist for non Euclidean spaces. The invariator design is convenient to estimate surface area and volume simultaneously. In recent years a number of new results have appeared which call for an updated survey. We include two new estimators, namely the a posteriori weighting estimator for surface area and volume, and the peak-and-valley formula for surface area.


2000 ◽  
Vol 32 (03) ◽  
pp. 648-662
Author(s):  
Yukinao Isokawa

We study Poisson-Voronoi tessellations in three-dimensional hyperbolic spaces, and give explicit expressions for mean surface area, mean perimeter length, and mean number of vertices of their cells. Furthermore we compare these mean characteristics with those for Poisson-Voronoi tessellations in three-dimensional Euclidean spaces. It is shown that, as the absolute value of the curvature of hyperbolic spaces increases from zero to infinity, these mean characteristics increase monotonically from those for the Euclidean case to infinity.


1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.


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