Introduction: Quadrangle geological maps from Mariner 10 data cover 45% [1] of the surface of Mercury at 1:5M scale, e.g. [2],[3]. Orbital MESSENGER data, which cover the entire planetary surface, can now be used to produce finer scale geological maps, including regions unseen by Mariner 10. Hokusai quadrangle (0–90° E; 22.5–66° N) is in the hemisphere unmapped by Mariner 10. It contains promin...

We define the notion of d i -regularity and regularity in generalized polygons, thus generalizing the notion of ‘regular point’ in a generalized quadrangle or hexagon. We show that a thick generalized polygon cannot contain too many regular points unless it is a projective plane, quadrangle or hexagon. For certain polygons (thick ‘odd’gons and 8-gons), we show that even a certain number of d2-r...

A conic of the Veronese surface in PG(5, 3) is a quadrangle. If one such quadrangle is replaced with its diagonal triangle, then one obtains a point model K for Witt’s 5–(12, 6, 1) design, the blocks being the hyperplane sections containing more than three (actually six) points of K. As such a point model is projectively unique, the present construction yields an easy coordinate–free approach t...

We propose an approach for automatically generating isotropic 2D quadrangle meshes from arbitrary domains with a fine control over sizing and orientation of the elements. At the heart of our algorithm is an optimization procedure that, from a coarse initial tiling of the 2D domain, enforces each of the desirable mesh quality criteria (size, shape, orientation, degree, regularity) one at a time,...

Let Q be a generalized quadrangle of order s with a regular point x. The set x⊥ together with all spans which are contained in x⊥ define a projective plane of order s. We introduce a property (Py) for every point y of Q noncollinear with x and prove that this property is equivalent with the regularity of the point y. We will use this to give an elementary proof for the following result: every g...

the mandan and deh-now bauxite deposits are located 40 km northeast of dehdasht in kohgiloye and boyer-ahmad province in the zagros simply folded belt. the deposits were formed in the oldest rocks of the area of late cretaceous age. the bauxite horizon is situated between sarvak and ilam formations. the aim of this study is to determine the mineralogy and texture relations of the deposits in or...

A hexagon quadrangle system of order n and index [HQS (n)] is a pair (X,H), where X is a finite set of n vertices and H is a collection of edge disjoint hexagon quadrangles (called blocks) which partitions the edge set of Kn, with vertex set X. A hexagon quadrangle system is said to be a 4-nesting [N(4) − HQS] if the collection of all the 4-cycles contained in the hexagon quadrangles is a /2-fo...

1 School of Computer Science & Engineering, Kyungpook National University, Daegu, Republic of Korea 2Universidad Politécnica de Valencia, Camino de Vera, S/N, 46022 Valencia, Spain 3 South Dakota State University, DEH (Old ECS) 123, Brookings, SD 57007, USA 4Department of Informatics, Electronic and Sistemistic, University of Calabria, Italy 5 Department of Electrical and Computer Engineering, ...