scholarly journals Using direct and contructive methods for the existence of origami models with given boundary conditions

2020 ◽  
Vol 01 (01) ◽  
pp. 54-71
Author(s):  
R. GERETSCHLAGER ◽  
◽  
S.L. KEELING ◽  

Whenever a unit square is folded to create an origami model in three-dimensional space, the edge of the paper forms a closed curve in space with a total length equal to four units. In this paper, some of the restrictions applicable to such resulting closed curves are derived in the case of classic origami models, in which none of the sections of the folded paper is curved in any way. This allows us to restrict the methods applied to those of classic euclidean geometry. Noting that it is of interest to determine origami models whose edges coincide with a polyline fulfilling the required conditions, we then proceed to show some methods for reconstructing the origami model if the boundary is known. Finally, some concrete reconstructions are demonstrated.

2020 ◽  
Vol 5 (5) ◽  
pp. 538-544 ◽  
Author(s):  
Istvan Szalay ◽  
B. Szalay

Using the theory of exploded numbers by the axiom–systems of real numbers and euclidean geometry, we introduce a geometry in the three–dimensional space which is different from the euclidean-, Bolyai – Lobachevsky- and spherical geometries. In this part the concept of extra-line and extra parallelism are detailed.


2019 ◽  
Vol 64 (11) ◽  
pp. 1069
Author(s):  
Yu. A. Sitenko ◽  
V. M. Gorkavenko

The two-dimensional space with a topological defect is a transverse section of the three-dimensional space with an Abrikosov–Nielsen–Olesen vortex, i.e. a gauge-flux-carrying tube which is impenetrable for quantum matter. Charged spinor matter field is quantized in this section with the most general mathematically admissible boundary condition at the edge of the defect. We show that a current and a magnetic field are induced in the vacuum. The dependence of results on the boundary conditions is studied, and we find that the requirement of finiteness of the total induced vacuum magnetic flux removes an ambiguity in the choice of boundary conditions. The differences between the cases of massive and massless spinor matters are discussed.


2020 ◽  
Vol 5 (8) ◽  
pp. 904-914
Author(s):  
Istvan Szalay ◽  
Balazs Szalay

Using the theory of exploded numbers by the axiom-systems of real numbers and Euclidean geometry, we introduce concept of extra - plane of the three-dimensional space. The extra - planes are visible subsets of super-planes which are exploded Euclidean planes. We investigate the main properties of extra-planes. We prove more similar properties of Euclidean planes and extra-planes, but with respect the parllelism there is an essential difference among them.


Author(s):  
Manuel Fernandez-Guasti

Elliptic scator algebra is possible in 1+n dimensions, n∈N. It is isomorphic to complex algebra in 1+1 dimensions, when the real part and any one hypercomplex component are considered. It is endowed with two representations: an additive one, where the scator components are represented as a sum; and a polar representation, where the scator components are represented as products of exponentials. Within the scator framework, De Moivre’s formula is generalized to 1+n dimensions in the so called victoria equation. This novel formula is then used to obtain compact expressions for the integer powers of scator elements. A scator in S1+n can be factored into a product of n scators that are geometrically represented as its projections onto n two dimensional planes. A geometric interpretation of scator multiplication in terms of rotations with respect to the scalar axis is expounded. The powers of scators, when the ratio of their director components is a rational number, lie on closed curves. For 1+2 dimensional scators, twisted curves in a three dimensional space are obtained. Collecting previous results, it is possible to evaluate the exponential of a scator element in 1+2 dimensions.


Axioms ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 250
Author(s):  
Manuel Fernandez-Guasti

Elliptic scator algebra is possible in 1+n dimensions, n∈N. It is isomorphic to complex algebra in 1 + 1 dimensions, when the real part and any one hypercomplex component are considered. It is endowed with two representations: an additive one, where the scator components are represented as a sum; and a polar representation, where the scator components are represented as products of exponentials. Within the scator framework, De Moivre’s formula is generalized to 1+n dimensions in the so called Victoria equation. This novel formula is then used to obtain compact expressions for the integer powers of scator elements. A scator in S1+n can be factored into a product of n scators that are geometrically represented as its projections onto n two dimensional planes. A geometric interpretation of scator multiplication in terms of rotations with respect to the scalar axis is expounded. The powers of scators, when the ratio of their director components is a rational number, lie on closed curves. For 1 + 2 dimensional scators, twisted curves in a three dimensional space are obtained. Collecting previous results, it is possible to evaluate the exponential of a scator element in 1 + 2 dimensions.


Sapere Aude ◽  
2019 ◽  
Vol 10 (19) ◽  
pp. 184-202
Author(s):  
Raquel Anna Sapunaru

A ideia de um espaço tridimensional começou a se formar no século XV. Antes disso, em um mundo dominado pelo aristotelismo, o espaço era vinculado à superfície e não ao volume. Foi através das artes que essa realidade começou a mudar. A perspectiva racional, definida aqui como um recurso gráfico que utiliza o efeito visual de linhas convergentes para criar a ilusão de tridimensionalidade do espaço e das formas representadas sobre uma superfície plana de um papel ou tela, nascida a partir de uma retomada da geometria euclidiana, entrou em cena para ficar no século XVI. Entre os muitos nomes que poderiam ser citados, destacaram-se o matemático e filósofo John Dee, o arquiteto e designer Filippo Brunelleschi, e o pintor e matemático Pierro della Francesca. Através da combinação das ideias e realizações desses três atores é possível entender uma época de transição entre o antigo e o moderno, em termos de ciência e arte.PALAVRAS-CHAVE: Espaço tridimencional. Geometria. Perspectiva racional. Filosofia e arte. ABSTRACTThe idea of a three-dimensional space began to form in the fifteenth century. Before that, in a world dominated by Aristotelianism, space was bound to the surface and not to the volume. It was through the arts that this reality began to change. The rational perspective, defined here as a graphic resource that uses the visual effect of converging lines to create the illusion of three-dimensionality of space and forms represented on a flat surface of a paper or canvas, born from a resumption of Euclidean geometry, came into the scene to stay in the sixteenth century. Among the many names that could be cited were the mathematician and philosopher John Dee, the architect and designer Filippo Brunelleschi, and the painter and mathematician Pierro della Francesca. By combining the ideas and achievements of these three actors it is possible to understand a time of transition between the old and the modern, in terms of science and art.KEYWORDS: Three-dimensional space. Geometry. Rational Perspective. Philosophy and Art.


1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.


2019 ◽  
Author(s):  
Jumpei Morimoto ◽  
Yasuhiro Fukuda ◽  
Takumu Watanabe ◽  
Daisuke Kuroda ◽  
Kouhei Tsumoto ◽  
...  

<div> <div> <div> <p>“Peptoids” was proposed, over decades ago, as a term describing analogs of peptides that exhibit better physicochemical and pharmacokinetic properties than peptides. Oligo-(N-substituted glycines) (oligo-NSG) was previously proposed as a peptoid due to its high proteolytic resistance and membrane permeability. However, oligo-NSG is conformationally flexible and is difficult to achieve a defined shape in water. This conformational flexibility is severely limiting biological application of oligo-NSG. Here, we propose oligo-(N-substituted alanines) (oligo-NSA) as a new peptoid that forms a defined shape in water. A synthetic method established in this study enabled the first isolation and conformational study of optically pure oligo-NSA. Computational simulations, crystallographic studies and spectroscopic analysis demonstrated the well-defined extended shape of oligo-NSA realized by backbone steric effects. The new class of peptoid achieves the constrained conformation without any assistance of N-substituents and serves as an ideal scaffold for displaying functional groups in well-defined three-dimensional space, which leads to effective biomolecular recognition. </p> </div> </div> </div>


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