Results 31 to 40 of about 208 (40)

Exact Nonnull Wavelike Solutions to Gravity with Quadratic Lagrangians

, 1999
Solutions to gravity with quadratic Lagrangians are found for the simple case where the only nonconstant metric component is the lapse $N$ and the Riemann tensor takes the form $R^{t}_{.itj}=-k_{i}k_{j}, i,j=1,2,3$; thus these solutions depend on cross ...
Roberts, Mark D.
core   +1 more source

Method of group foliation, hodograph transformation and non-invariant solutions of the Boyer-Finley equation

, 2003
We present the method of group foliation for constructing non-invariant solutions of partial differential equations on an important example of the Boyer-Finley equation from the theory of gravitational instantons.
Sheftel, M. B.
core   +1 more source

Generating potentials via difference equations

, 2006
The condition for pressure isotropy, for spherically symmetric gravitational fields with charged and uncharged matter, is reduced to a recurrence equation with variable, rational coefficients.
Debnath, Delgaty, Durgapal, Durgapal, Finch, Ivanov, John, Maharaj, Mak, Sharma, Stephani   +10 more
core   +1 more source

New anisotropic models from isotropic solutions

, 2005
We establish an algorithm that produces a new solution to the Einstein field equations, with an anisotropic matter distribution, from a given seed isotropic solution.
Bowers, Chaisi, Chaisi, Dev, Dev, Gokhroo, Herrera, Herrera, Ivanov, Maharaj, Maharaj, Mak, Mak, Rhoades, Saslaw, Saslaw, Sharma, Stephani, Wolfram   +18 more
core   +2 more sources

The Entropy of Lagrange-Finsler Spaces and Ricci Flows

, 2007
We formulate a statistical analogy of regular Lagrange mechanics and Finsler geometry derived from Grisha Perelman's functionals generalized for nonholonomic Ricci flows. There are elaborated explicit constructions when nonholonomically constrained flows
Antonelli, Bao, Bejancu, Cao, Hamilton, Miron, Miron R., Mrugala, Rapoport, Ruppeiner, Ruppeiner, Salamon, Sergiu I. Vacaru, Tsallis, Vacaru, Vacaru, Vacaru, Vacaru, Vacaru, Vacaru, Vacaru   +20 more
core   +4 more sources

Partner symmetries of the complex Monge-Ampere equation yield hyper-Kahler metrics without continuous symmetries

, 2003
We extend the Mason-Newman Lax pair for the elliptic complex Monge-Amp\`ere equation so that this equation itself emerges as an algebraic consequence. We regard the function in the extended Lax equations as a complex potential.
A A Malykh, Aliev A N, Atiyah M, Atiyah M F, Bluman G W, Boyer C P, Dunajskii M, Dunajskii M, Goldblatt E, Hitchin N J, Lechtenfeld O, Lie S, M B Sheftel, Malykh A A, Malykh A A, Malykh A A, Martina L, Mason L J, Mason L J, Nutku Y, Nutku Y, Olver P, Ovsiannikov L V, Popov A D, Vessiot E, Y Nutku   +25 more
core   +1 more source

Penrose junction conditions with Λ : geometric insights into low-regularity metrics for impulsive gravitational waves. [PDF]

Gen Relativ Gravit, 2022
Podolský J, Steinbauer R.
europepmc   +1 more source

Analysis of transmission dynamics of COVID-19 via closed-form solutions of a susceptible-infectious-quarantined-diseased model with a quarantine-adjusted incidence function. [PDF]

Math Methods Appl Sci, 2021
Naz R, Al-Raeei M.
europepmc   +1 more source

Complete classification of spatial surfaces with parallel mean curvature vector in arbitrary non-flat pseudo-Riemannian space forms

Open Mathematics, 2009
Chen Bang-Yen
doaj   +1 more source

Cut-and-paste for impulsive gravitational waves with Λ: the mathematical analysis. [PDF]

Lett Math Phys
Sämann C, Schinnerl B, Steinbauer R, Švarc R.   +3 more
europepmc   +1 more source