scholarly journals Antipodal Identification in the Schwarzschild Spacetime

2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Miguel Socolovsky ◽  

"Through a Möbius transformation, we study aspects like topology, ligth cones, horizons, curvature singularity, lines of constant Schwarzschild coordinates r and t, null geodesics, and transformed metric, of the spacetime (SKS/2)^' that results from: i) the antipode identification in the Schwarzschild-Kruskal-Szekeres (SKS) spacetime, and ii) the suppression of the consequent conical singularity. In particular, one obtains a non simply-connected topology: (SKS/2)^' = R^2* ×S^2 and, as expected, bending light cones."

2017 ◽  
Vol E100.C (10) ◽  
pp. 918-923
Author(s):  
Sonshu SAKIHARA ◽  
Masaru TAKANA ◽  
Naoki SAKAI ◽  
Takashi OHIRA

Author(s):  
David Berman ◽  
Hugo Garcia-Compean ◽  
Paulius Miškinis ◽  
Miao Li ◽  
Daniele Oriti ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Muhammad Asif ◽  
Sibgha Mairaj ◽  
Zafar Saeed ◽  
M. Usman Ashraf ◽  
Kamal Jambi ◽  
...  

The nonlinear transformation concedes as S-box which is responsible for the certainty of contemporary block ciphers. Many kinds of S-boxes are planned by various authors in the literature. Construction of S-box with a powerful cryptographic analysis is the vital step in scheming block cipher. Through this paper, we give more powerful and worthy S-boxes and compare their characteristics with some previous S-boxes employed in cryptography. The algorithm program planned in this paper applies the action of projective general linear group P G L 2 , G F 2 8 on Galois field G F 2 8 . The proposed S-boxes are constructed by using Mobius transformation and elements of Galois field. By using this approach, we will encrypt an image which is the preeminent application of S-boxes. These S-boxes offer a strong algebraic quality and powerful confusion capability. We have tested the strength of the proposed S-boxes by using different tests, BIC, SAC, DP, LP, and nonlinearity. Furthermore, we have applied these S-boxes in image encryption scheme. To check the strength of image encryption scheme, we have calculated contrast, entropy, correlation, energy, and homogeneity. The results assured that the proposed scheme is better. The advantage of this scheme is that we can secure our confidential image data during transmission.


2021 ◽  
Vol 5 (3) ◽  
pp. 92
Author(s):  
Pavel Trojovský ◽  
K Venkatachalam

In 2021, Mork and Ulness studied the Mandelbrot and Julia sets for a generalization of the well-explored function ηλ(z)=z2+λ. Their generalization was based on the composition of ηλ with the Möbius transformation μ(z)=1z at each iteration step. Furthermore, they posed a conjecture providing a relation between the coefficients of (each order) iterated series of μ(ηλ(z)) (at z=0) and the Catalan numbers. In this paper, in particular, we prove this conjecture in a more precise (quantitative) formulation.


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