The aftermath of the intermediate value theorem.
The Approximation of Generalized Turning Points by Projection Methods with Superconvergence to the Critical Parameter.
The coincidence index for fundamentally contractible multivalued maps with nonconvex values
We study a coincidence problem of the form A(x) ∈ ϕ (x), where A is a linear Fredholm operator with nonnegative index between Banach spaces and ϕ is a multivalued A-fundamentally contractible map (in particular, it is not necessarily compact). The main tool is a coincidence index, which becomes the well known Leray-Schauder fixed point index when A=id and ϕ is a compact singlevalued map. An application to boundary value problems for differential equations in Banach spaces is given.
The concentration-compactness principle in the calculus of variations. The locally compact case, part 1
The existence of bounded solutions for differential equations in Hilbert spaces
The existence of bounded solutions for equations x' = A(t)x + r(x,t) is proved, where the linear part is exponentially dichotomic and the nonlinear term r satisfies some weak conditions.
The interaction of linear boundary value and nonlinear functional conditions
The existence of solutions is studied for certain nonlinear differential equations with both linear and nonlinear conditions
The Product Formula for the Topological Degree of Strict ...-Contractions.
The ranges of nonlinear operators of the polynomial type
The Schauder-Tychonoff Fixed Point Theorem and Applications
The semilinear Feng and FMV spectra.
The solution of a Fučík's conjecture
The topological degree and fixed points of DC-mappings
Théorèmes de Nikišin
Theorems of existence and multiplicity for nonlinear elliptic problems with noninvertible linear part
Three methods for the study of semilinear equations at resonance
Three methods for the study of the solvability of semilinear equations with noninvertible linear parts are compared: the alternative method, the continuation method of Mawhin and a new perturbation method [22]-[27]. Some extension of the last method and applications to differential equations in Banach spaces are presented.
Topological degree for ultimately compact multivalued vector fields in topological vector spaces
Transformationseigenschaften endlicher Ketten und allgemeine Verzweigungsaussagen.