1.

Record Nr.

UNINA9911076544203321

Titolo

Temporary appropriations. June 26, 1951. -- Committed to the Committee of the Whole House on the State of the Union and ordered to be printed

Pubbl/distr/stampa

[Washington, D.C.] : , : [U.S. Government Printing Office], , 1951

Descrizione fisica

1 online resource (1 page)

Collana

House report / 82nd Congress, 1st session. House ; ; no. 655

[United States congressional serial set] ; ; [serial no. 11497]

Altri autori (Persone)

CannonClarence <1879-1964> (Democrat (MO))

Soggetti

Expenditures, Public

Legislative materials.

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Note generali

Batch processed record: Metadata reviewed, not verified. Some fields updated by batch processes.

FDLP item number not assigned.



2.

Record Nr.

UNINA9911099897803321

Autore

Berestycki H (Henri)

Titolo

Asymptotic Spreading for General Heterogeneous Fisher-KPP Type Equations

Pubbl/distr/stampa

Providence : , : American Mathematical Society, , 2022

©2022

ISBN

9781470472818

1470472813

Edizione

[1st ed.]

Descrizione fisica

1 online resource (112 pages)

Collana

Memoirs of the American Mathematical Society ; ; v.280

Classificazione

35B4035B2735K5735B5035K1035P0547B6549L25

Altri autori (Persone)

NadinGregoire

Disciplina

515/.3534

515.3534

Soggetti

Reaction-diffusion equations

Differential equations, Parabolic - Asymptotic theory

Partial differential equations -- Qualitative properties of solutions -- Asymptotic behavior of solutions

Partial differential equations -- Qualitative properties of solutions -- Homogenization; equations in media with periodic structure

Partial differential equations -- Parabolic equations and systems -- Reaction-diffusion equations

Partial differential equations -- Qualitative properties of solutions -- Maximum principles

Partial differential equations -- Parabolic equations and systems -- Second-order parabolic equations

Partial differential equations -- Spectral theory and eigenvalue problems -- General topics in linear spectral theory

Operator theory -- Special classes of linear operators -- Positive operators and order-bounded operators

Calculus of variations and optimal control; optimization -- Hamilton-Jacobi theories, including dynamic programming -- Viscosity solutions

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Nota di contenuto

A general formula for the expansion sets -- Exact asymptotic spreading speed in different frameworks -- Properties of the generalized principal eigenvalues -- Proof of the spreading property -- The homogeneous, periodic and compactly supported cases -- The



almost periodic case -- The uniquely ergodic case -- The radially periodic case -- The space-independent case -- The directionally homogeneous case -- Proof of the spreading property with the alternative definition of the expansion sets and applications -- Further examples and other open problems.

Sommario/riassunto

"In this monograph, we review the theory and establish new and general results regarding spreading properties for heterogeneous reaction-diffusion equations. These are concerned with the dynamics of the solution starting from initial data with compact support. The nonlinearity f is of Fisher-KPP type, and admits 0 as an unstable steady state and 1 as a globally attractive one (or, more generally, admits entire solutions , where is unstable and is globally attractive). Here, the coefficients are only assumed to be uniformly elliptic, continuous and bounded in . To describe the spreading dynamics, we construct two non-empty star-shaped compact sets such that for all compact set (resp. all closed set , one has lim . The characterizations of these sets involve two new notions of generalized principal eigenvalues for linear parabolic operators in unbounded domains. In particular, it allows us to show that and to establish an exact asymptotic speed of propagation in various frameworks. These include: almost periodic, asymptotically almost periodic, uniquely ergodic, slowly varying, radially periodic and random stationary ergodic equations. In dimension N, if the coefficients converge in radial segments, again we show that and this set is characterized using some geometric optics minimization problem. Lastly, we construct an explicit example of non-convex expansion sets"--