Bifurcation of nonlinear elliptic system from the first eigenvalue.
Bound sets and two-point boundary value problems for second order differential systems
The solvability of second order differential systems with the classical separated or periodic boundary conditions is considered. The proofs use special classes of curvature bound sets or bound sets together with the simplest version of the Leray-Schauder continuation theorem. The special cases where the bound set is a ball, a parallelotope or a bounded convex set are considered.
Boundary value problems for differential equations with deviating arguments
Boundary value problems for nonlinear perturbations of some ϕ-Laplacians
This paper surveys a number of recent results obtained by C. Bereanu and the author in existence results for second order differential equations of the form (ϕ(u'))' = f(t,u,u') submitted to various boundary conditions. In the equation, ϕ: ℝ → ≤ ]-a,a[ is a homeomorphism such that ϕ(0) = 0. An important motivation is the case of the curvature operator, where ϕ(s) = s/√(1+s²). The problems are reduced to fixed point problems in suitable function space, to which Leray-Schauder...
Bourgin–Yang-type theorem for -compact perturbations of closed operators. I: The case of index theories with dimension property.
Brouwer degree, equivariant maps and tensor powers.