zbMATH — the first resource for mathematics

Geometry Search for the term Geometry in any field. Queries are case-independent.
Funct* Wildcard queries are specified by * (e.g. functions, functorial, etc.). Otherwise the search is exact.
"Topological group" Phrases (multi-words) should be set in "straight quotation marks".
au: Bourbaki & ti: Algebra Search for author and title. The and-operator & is default and can be omitted.
Chebyshev | Tschebyscheff The or-operator | allows to search for Chebyshev or Tschebyscheff.
"Quasi* map*" py: 1989 The resulting documents have publication year 1989.
so: Eur* J* Mat* Soc* cc: 14 Search for publications in a particular source with a Mathematics Subject Classification code (cc) in 14.
"Partial diff* eq*" ! elliptic The not-operator ! eliminates all results containing the word elliptic.
dt: b & au: Hilbert The document type is set to books; alternatively: j for journal articles, a for book articles.
py: 2000-2015 cc: (94A | 11T) Number ranges are accepted. Terms can be grouped within (parentheses).
la: chinese Find documents in a given language. ISO 639-1 language codes can also be used.

a & b logic and
a | b logic or
!ab logic not
abc* right wildcard
"ab c" phrase
(ab c) parentheses
any anywhere an internal document identifier
au author, editor ai internal author identifier
ti title la language
so source ab review, abstract
py publication year rv reviewer
cc MSC code ut uncontrolled term
dt document type (j: journal article; b: book; a: book article)
Dynamics of a nonautonomous predator–prey system with the Beddington-DeAngelis functional response. (English) Zbl 1051.34033
The authors study the dynamics of a nonautonomous predator-prey system with Beddington-DeAngelis functional response. They argue that this system is more realistic than the Holling type response. Then they derive sufficient conditions for the persistence and global stability of the system. Motivated by the observed environmental changes, they study the case when all the coefficients are periodic or almost periodic with a given period. They derive sufficient conditions for the existence of positive periodic solutions and of boundary periodic solutions (where the predator extincts). Similar results are obtained for the almost-periodic case. They performed numerical simulations which has indicated that some of their conditions can be relaxed. In the reviewer’s opinion this is a very impressive work.

34C25Periodic solutions of ODE
92D25Population dynamics (general)
34C27Almost and pseudo-almost periodic solutions of ODE