Znanstveno-stručni časopis
Hrvatskog društva za geometriju i grafiku

Scientific and Professional Journal of the Croatian Society for Geometry and Graphics

Vladimir Volenec (volenec@math.hr)

Pascal-Brianchon Sets in Pappian Projective Planes

It is well-known that Pascal and Brianchon theorems characterize conics in a Pappian projective plane. But, using these theorems and their modifications we shall show that the notion of a conic (or better a Pascal-Brianchon set) can be defined without any use of theory of projectivities or of polarities as usually.

Keywords: conic, Pascal set, Pascal-Brianchon set
Josip Dvornik (dvornik@grad.hr)

Computer Methods for Problem Solving

There are a lot of computer methods for solving mathematical and other problems. Generally, they can be classified into numerical, symbolic and analytic, as well as heuristic methods which may include "artificial intelligence". For different problems, different approaches are needed. In recent years the development of all the three groups of methods has been very fast. Owing to an increasing number of hybrid methods which combine analitic, numerical and heuristic approach, some very difficult problems have been solved successfully.

Keywords: hartificial intelligence, heuristic methods, numerical methods, problem solving, symbolic method


Jasna Kos-Modor, Ema Jurkin (ejurkin@rudar.rgn.hr)

The Layer

The layer is the basic unit of sediment rocks. In the projection with heights the presentation of the regular layer limited with two parallel planes is shown. Profile of the layer is constructed and the thickness and inclination of layer are determined. Two cases of setting and solving the layer are demonstrated.

Keywords: projection with heights, layer, outcrop line, thickness of layer

Nikoleta Sudeta, Ivan Petrunić (nsudeta@arhitekt.hr)

Vaults as Parts of Sphere in Orthogonal Axonomerty

In order to represent an architectural structure we often use axonometric methods. The most convinient type of representing vaults as parts of spheres is orthogonal axonomerty. The paper presents simple constructons of axonometric representations of some architectural dome (spherical, bohemian and pendentive) with view from above and from below.

Keywords: dome, contour, ellipse, orthogonal axonomerty