Ginosar and the first author reduced the surjectivity of the norm map NG for a group G to the surjectivity of the norm maps for its elementary abelian subgroups; more precisely, they proved that NG : R → R G is surjective if and only if NU : R → R U is surjective for every elementary abelian subgroup U of G (see [2, Theorem 1]). The R -linearity of NU implies that it is surjective if and only t...

We introduce a new model for simulating natural phenomena. We address several issues: topology, basic set properties like injectivity and surjectivity, reversibility, and decidability questions about a special kind of conservation law called grain conservation and ultimate periodicity.

Iterative methods based on small functions are used both to show local surjectivity of certain operators and a fixed point property of mappings on scales of complete metric spaces.

In this paper we construct new obstructions for the surjectivity of the Johnson homomorphism of the automorphism group of a free group. We also determine the structure of the cokernel of the Johnson homomorphism for degree 2 or 3.

‎In this paper‎, ‎we study weighted composition operators between Lipschitz algebras of complex-valued bounded functions on metric spaces‎, ‎not necessarily compact‎. ‎We give necessary and sufficient conditions for the injectivity and the surjectivity of these operators‎. ‎We also obtain sufficient and necessary conditions for a weighted composition operator between these spaces to be compact.

In this paper the problem of system equivalence is tackled for a rather general class of linear time-invariant systems. We consider AR-systems described by linear continuous shift-invariant operators with finite memory, acting on Frechet-signal spaces, containing the space £(lR) of infinitely differentiable functions on lR. This class is in one-one correspondence with matrices of suitable sizes...

We study the surjectivity of adelic Galois representation associated to Drinfeld $\mathbb {F}_q[T]$-modules over {F}_q(T)$ rank 2 when $q$ is even or $q=3$.