The Gordian complex of theta-curves

2021 ◽  
Author(s):  
Sahil Joshi ◽  
Madeti Prabhakar
Keyword(s):  
Lower Bound ◽  
Euclidean Space ◽  
Simplicial Complex ◽  
Infinite Family ◽  
Dimensional Euclidean Space ◽  
3 Dimensional

In this paper, we study the Gordian metric on the set of all theta-curves and give a lower bound of it. We define the Gordian complex of theta-curves, which is a simplicial complex whose vertices consist of all theta-curves in the 3-dimensional Euclidean space [Formula: see text]. We show that for any given theta-curve [Formula: see text], there exists an infinite family of theta-curves containing [Formula: see text] such that the Gordian distance between any two distinct members of this family is equal to one.

scholarly journals CURVES ON RULED SURFACES UNDER INFINITESIMAL BENDING

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marija Najdanović ◽  
Miroslav Maksimović ◽  
Ljubica Velimirović
Keyword(s):  
Euclidean Space ◽  
Ruled Surfaces ◽  
Dimensional Euclidean Space ◽  
Hyperbolic Paraboloid ◽  
3 Dimensional ◽  
Infinitesimal Bending

Infinitesimal bending of curves lying with a given precision on ruled surfaces in 3-dimensional Euclidean space is studied. In particular, the bending of curves on the cylinder, the hyperbolic paraboloid and the helicoid are considered and appropriate bending fields are found. Some examples are graphically presented.

scholarly journals On Various Definitions of Capacity and Related Notions

1967 ◽  
Vol 30 ◽  
pp. 121-127 ◽  
Author(s):  
Makoto Ohtsuka
Keyword(s):  
Euclidean Space ◽  
Positive Charge ◽  
Dimensional Euclidean Space ◽  
3 Dimensional ◽  
Electric Capacity ◽  
De La Vallée Poussin

The electric capacity of a conductor in the 3-dimensional euclidean space is defined as the ratio of a positive charge given to the conductor and the potential on its surface. The notion of capacity was defined mathematically first by N. Wiener [7] and developed by C. de la Vallée Poussin, O. Frostman and others. For the history we refer to Frostman’s thesis [2]. Recently studies were made on different definitions of capacity and related notions. We refer to M. Ohtsuka [4] and G. Choquet [1], for instance. In the present paper we shall investigate further some relations among various kinds of capacity and related notions. A part of the results was announced in a lecture of the author in 1962.

scholarly journals Surfaces of Finite III-type

2021 ◽  
Vol 15 ◽  
pp. 190-194
Author(s):  
Hassan Al-Zoubi
Keyword(s):  
Euclidean Space ◽  
Fundamental Form ◽  
Principal Curvature ◽  
Gauss Curvature ◽  
Dimensional Euclidean Space ◽  
Surfaces Of Revolution ◽  
3 Dimensional ◽  
The Third ◽  
Third Fundamental Form ◽  
Special Case

In this paper, we consider surfaces of revolution in the 3-dimensional Euclidean space E3 with nonvanishing Gauss curvature. We introduce the finite Chen type surfaces with respect to the third fundamental form of the surface. We present a special case of this family of surfaces of revolution in E3, namely, surfaces of revolution with R is constant, where R denotes the sum of the radii of the principal curvature of a surface.

scholarly journals On the second Gaussian curvature of ruled surfaces in Euclidean $3$-space

2006 ◽  
Vol 37 (3) ◽  
pp. 221-226 ◽  
Author(s):  
Dae Won Yoon
Keyword(s):  
Euclidean Space ◽  
Gaussian Curvature ◽  
Mean Curvature ◽  
Ruled Surface ◽  
Ruled Surfaces ◽  
Dimensional Euclidean Space ◽  
3 Dimensional ◽  
The Mean ◽  
Second Gaussian Curvature

In this paper, we mainly investigate non developable ruled surface in a 3-dimensional Euclidean space satisfying the equation $K_{II} = KH$ along each ruling, where $K$ is the Gaussian curvature, $H$ is the mean curvature and $K_{II}$ is the second Gaussian curvature.

scholarly journals Equilateral Sets and a Schütte Theorem for the 4-norm

2014 ◽  
Vol 57 (3) ◽  
pp. 640-647
Author(s):  
Konrad J. Swanepoel
Keyword(s):  
Lower Bound ◽  
Euclidean Space ◽  
Dimensional Euclidean Space ◽  
Minimum Distances ◽  
Equilateral Sets ◽  
Sharp Lower Bound ◽  
Elegant Proof

AbstractA well-known theorem of Schütte (1963) gives a sharp lower bound for the ratio of the maximum and minimum distances between n + 2 points in n-dimensional Euclidean space. In this note we adapt Bárány’s elegant proof (1994) of this theorem to the space . This gives a new proof that the largest cardinality of an equilateral set in is n + 1 and gives a constructive bound for an interval (4–εn, 4 + εn) of values of p close to 4 for which it is known that the largest cardinality of an equilateral set in is n + 1.

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