Nonlinear monotone semigroups and viscosity solutions
On an arbitrary reflexive Banach space, we build asymptotic observers for an abstract class of nonlinear control systems with possible compact outputs. An important part of this paper is devoted to various examples, where we discuss the existence of persistent inputs which make the system observable. These results make a wide generalization to a nonlinear framework of previous works on the observation problem in infinite dimension (see [11, 18, 22, 26, 27, 38, 40] and other references therein).
On an arbitrary reflexive Banach space, we build asymptotic observers for an abstract class of nonlinear control systems with possible compact outputs. An important part of this paper is devoted to various examples, where we discuss the existence of persistent inputs which make the system observable. These results make a wide generalization to a nonlinear framework of previous works on the observation problem in infinite dimension (see [11,18,22,26,27,38,40] and other references therein).
In this paper, we prove an existence theorem for the pseudo-non-local Cauchy problem , x₀(t₀) = x₀ - g(x), where A is the infinitesimal generator of a C₀ semigroup of operator on a Banach space. The functions f,g are weakly-weakly sequentially continuous and the integral is taken in the sense of Pettis.
Vengono dati nuovi teoremi di regolarità per le soluzioni dell'equazione nel caso in cui è il generatore infinitesimale di un semigruppo analitico in uno spazio di Banach e è una funzione continua.
Given a family of (W) contractions on a reflexive Banach space X we discuss unrestricted sequences . We show that they converge weakly to a common fixed point, which depends only on x and not on the order of the operators if and only if the weak operator closed semigroups generated by are right amenable.
The existence, uniqueness and asymptotic stability of weak solutions of functional-differential abstract nonlocal Cauchy problems in a Banach space are studied. Methods of m-accretive operators and the Banach contraction theorem are applied.
We prove that for each linear contraction T : X → X (∥T∥ ≤ 1), the subspace F = {x ∈ X : Tx = x} of fixed points is 1-complemented, where X is a suitable subspace of L¹(E*) and E* is a separable dual space such that the weak and weak* topologies coincide on the unit sphere. We also prove some related fixed point results.