scholarly journals Cauchy Problems for Evolutionary Pseudodifferential Equations overp-Adic Field

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Bo Wu ◽  
Yin Li ◽  
Weiyi Su

We study a class of evolutionary pseudodifferential equations of the second order int,  (∂2u(t,x)/∂t2+2a2Tα/2(∂u(t,x)/∂t)+b2Tαu(t,x)+c2u(t,x)=q(t,x)), wheret∈(0,z]andTαis pseudodifferential operator inx∈Qp, which defined by Weiyi Su in 1992. We obtained the exact solutions to the equations which belong to mixed classes of real andp-adic functions.

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
R. Naz ◽  
I. Naeem ◽  
F. M. Mahomed

This paper analyzes the first integrals and exact solutions of mathematical models of epidemiology via the partial Lagrangian approach by replacing the three first-order nonlinear ordinary differential equations by an equivalent system containing one second-order equation and a first-order equation. The partial Lagrangian approach is then utilized for the second-order ODE to construct the first integrals of the underlying system. We investigate the SIR and HIV models. We obtain two first integrals for the SIR model with and without demographic growth. For the HIV model without demography, five first integrals are established and two first integrals are deduced for the HIV model with demography. Then we utilize the derived first integrals to construct exact solutions to the models under investigation. The dynamic properties of these models are studied too. Numerical solutions are derived for SIR models by finite difference method and are compared with exact solutions.


Kybernetes ◽  
2010 ◽  
Vol 39 (6) ◽  
pp. 954-960
Author(s):  
Yongzhong Huang ◽  
Yan Feng

2008 ◽  
Vol 102 (2) ◽  
pp. 283 ◽  
Author(s):  
Massimo Cicognani ◽  
Fumihiko Hirosawa

We consider the loss of regularity of the solution to the backward Cauchy problem for a second order strictly hyperbolic equation on the time interval $[0,T]$ with time depending coefficients which have a singularity only at the end point $t=0$. The main purpose of this paper is to show that the loss of regularity of the solution on the Gevrey scale can be described by the order of differentiability of the coefficients on $(0,T]$, the order of singularities of each derivatives as $t\to0$ and a stabilization condition of the amplitude of oscillations described by an integral on $(0,T)$. Moreover, we prove the optimality of the conditions for $C^\infty$ coefficients on $(0,T]$ by constructing a counterexample.


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