Strong submeasures and applications to non-compact dynamical systems

A strong submeasure on a compact metric space X is a sub-linear and bounded operator on the space of continuous functions on X. A strong submeasure is positive if it is non-decreasing. By the Hahn–Banach theorem, a positive strong submeasure is the supremum of a non-empty collection of measures whose masses are uniformly bounded from above. There are many natural examples of continuous maps of the form $f:U\rightarrow X$ , where X is a compact metric space and $U\subset X$ is an open-dense subset, where f cannot extend to a reasonable function on X. We can mention cases such as transcendental maps of $\mathbb {C}$ , meromorphic maps on compact complex varieties, or continuous self-maps $f:U\rightarrow U$ of a dense open subset $U\subset X$ where X is a compact metric space. For the aforementioned mentioned the use of measures is not sufficient to establish the basic properties of ergodic theory, such as the existence of invariant measures or a reasonable definition of measure-theoretic entropy and topological entropy. In this paper we show that strong submeasures can be used to completely resolve the issue and establish these basic properties. In another paper we apply strong submeasures to the intersection of positive closed $(1,1)$ currents on compact Kähler manifolds.

q-Differences theorems for meromorphic maps of several complex variables intersecting hypersurfaces

In this paper, we show some [Formula: see text]-difference analogues of the second main theorems for algebraically nondegenerate meromorphic mappings over the field [Formula: see text] of zero-order meromorphic functions in [Formula: see text] satisfying [Formula: see text] intersecting hypersurfaces, located in subgeneral position in [Formula: see text], where [Formula: see text] and [Formula: see text] may be different. As an application, we give some unicity theorems for meromorphic mappings of [Formula: see text] into [Formula: see text] under the growth condition “order [Formula: see text]”, which are analogous to Picard’s theorems.

On n-th roots of meromorphic maps

Let S be a connected Riemann surface and let φ: S → Ĉ bebranched covering map of nite type. If n ≥ 2,then we describe a simple geometrical necessary and sucient condition for the existence of some n-th root, that is, a meromorphic map ψ: S → Ĉ such that φ = ψn.