scholarly journals Conformal flatness of circle bundle metric

1998 ◽  
Vol 22 (2) ◽  
pp. 349-355
Author(s):  
Takafumi Satou
2015 ◽  
Vol 48 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Gianluca Bande ◽  
David E. Blair ◽  
Amine Hadjar
Keyword(s):  

2019 ◽  
Vol 28 (03) ◽  
pp. 1950051
Author(s):  
M. Sharif ◽  
Sobia Sadiq

The purpose of this paper is to construct spherically symmetric models for anisotropic matter configurations by imposing conformally flat conditions. This work is done for a relatively moving observer with matter using two types of polytropic equations of state. We evaluate the corresponding conservation equation, mass equation as well as energy constraints for both choices of equations of state. The conformal flatness is employed to find a specific form of anisotropy which aids study to spherical polytropic configurations. It is found that the first model satisfies all the energy conditions while the second model does not meet the dominant energy bound. It is also found that both models remain stable throughout the evolution.


2003 ◽  
Vol 05 (04) ◽  
pp. 569-627 ◽  
Author(s):  
Joshua M. Sabloff

Let M be a circle bundle over a Riemann surface that supports a contact structure transverse to the fibers. This paper presents a combinatorial definition of a differential graded algebra (DGA) that is an invariant of Legendrian knots in M. The invariant generalizes Chekanov's combinatorial DGA invariant of Legendrian knots in the standard contact 3-space using ideas from Eliashberg, Givental, and Hofer's contact homology. The main difficulty lies in dealing with what are ostensibly 1-parameter families of generators for the DGA; these are solved using "Morse–Bott" techniques. As an application, the invariant is used to distinguish two Legendrian knots that are smoothly isotopic, realize a nontrivial homology class, but are not Legendrian isotopic.


2006 ◽  
Vol 97 (17) ◽  
Author(s):  
Kōji Uryū ◽  
François Limousin ◽  
John L. Friedman ◽  
Eric Gourgoulhon ◽  
Masaru Shibata

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