| Cím: | On the existence of periodic solutions for linear inhomogeneous and quasilinear functional differential equations. |
| Szerző: | Hatvani, L.; Krisztin, T. |
| Forrás: | J. Differ. Equations 97, No.1, 1-15 (1992). |
| Nyelv: | English |
| Absztrakt: | The equation $x'(t)=\int\sp{+\infty}\sb{-\infty}(dE(s))x(t+s)+f(t)$
is considered with $T$-periodic $f$. Associate the characteristic
equation $\text{det} \Delta(\mu)=0$ $\Delta(\mu)=\mu I-\int\sp{+\infty}\sb{-
\infty}e\sp{\mu s}dE(s)$. Define $\mu\sb R={2k\pi i\over T}$
and let $\hat f(k)$ be the $k$th Fourier coefficient of $f$.
An elementary proof is given for the following: The equation
has a $T$-periodic solution iff $a\hat f(k)=0$ for all row vectors
$a$ for which $a\Delta(\mu\sb k)=0$. For the ``if'' part a proof
using Leray-Schauder arguments allows generalizations to nonlinear
situations.}
\RV{A.Halanay (Bucure\c{s}ti) |
| Letöltés: | | Zentralblatt |