The typical phenomena in geographic space are 2-dimensional or 3dimensional in nature, yet people often conceptualize some of them as 1dimensional entities embedded in a 2-dimensional space—rivers have widths and depths, and extent across the surface of the Earth, but for some tasks they are thought of as linear objects; likewise, roads as travel paths have widths as they wind through the lands...

Abstract. In this paper we classify a linear family of Lie brackets on the space of rectangular matrices Mat(n×m, K) and we give an analogue of the Ado’s Theorem. We give also a similar classification on the algebra of the square matrices Mat(n, K) and as a consequence, we prove that we can’t built a faithful representation of the (2n + 1)-dimensional Heisenberg Lie algebra Hn in a vector space...

This essay is intended to be a self-contained if rather brief introduction to Lie algebras. The first several sections deal with Lie algebras as spaces of invariant vector fields on a Lie group. The very first sections are concerned with different ways to consider vector fields. This early treatment is intended, among other things, to motivate the eventual introduction of abstract Lie algebras,...

In this paper we determine the number of the meaningful compositions of higher order of the differential operations and Gateaux directional derivative.

We present results of a weak gravitational lensing survey of six X-ray selected high-redshift clusters of galaxies. We find that the masses of the clusters derived from weak lensing are comparable to those derived from the X-ray observations. We show that many of the clusters have significant substructure not observed in the X-ray observations and that for the more massive clusters a singular i...

In this paper we shall repair some errors and fill some gaps in the inner model theory of [2]. The problems we shall address affect some quite basic definitions and proofs. We shall be concerned with condensation properties of canonical inner models constructed from coherent sequences ~ E of extenders as in [2]. Condensation results have the general form: if x is definable in a certain way over...

Abstract. In this paper we classify a linear family of Lie brackets on the space of rectangular matrices Mat(n×m, K) and we give an analogue of the Ado’s Theorem. We give also a similar classification on the algebra of the square matrices Mat(n, K) and as a consequence, we prove that we can’t built a faithful representation of the (2n + 1)-dimensional Heisenberg Lie algebra Hn in a vector space...

In this paper we introduce the “do not touch” condition for squares in the discrete plane. We say that two squares “do not touch” if they do not share any vertex or any segment of an edge. Using this condition we define a covering of the discrete plane, the covering can be strong or weak, regular or non-regular. For simplicity, in this article, we will restrict our attention to regular covering...

Let H be a countable infinite homogeneous relational structure. If H is indivisible then it is weakly indivisible and if it is weakly indivisible then it is age indivisible. There are examples of countable infinite homogeneous structures which are weakly indivisible but not indivisible. It is a natural question to ask for examples of countable age indivisible homogenous structures which are not...

Geoffrey Grimmett and Svante Janson Abstra t. Pick n points independently at random in R2 , according to a prescribed probability measure μ, and let ∆ 1 ≤ ∆ 2 ≤ . . . be the areas of the n 3 triangles thus formed, in non-decreasing order. If μ is absolutely continuous with respect to Lebesgue measure, then, under weak conditions, the set {n∆ i : i ≥ 1} converges as n → ∞ to a Poisson process wi...