Symmetry groups associated with tilings on a flat torus

2015 ◽  
Vol 71 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Mark L. Loyola ◽  
Ma. Louise Antonette N. De Las Peñas ◽  
Grace M. Estrada ◽  
Eko Budi Santoso
Keyword(s):  
Symmetry Group ◽  
Geometric Modeling ◽  
Three Dimensional ◽  
Symmetry Groups ◽  
Flat Torus ◽  
Color Symmetry ◽  
Symmetry Properties

This work investigates symmetry and color symmetry properties of Kepler, Heesch and Laves tilings embedded on a flat torus and their geometric realizations as tilings on a round torus in Euclidean 3-space. The symmetry group of the tiling on the round torus is determined by analyzing relevant symmetries of the planar tiling that are transformed to axial symmetries of the three-dimensional tiling. The focus on studying tilings on a round torus is motivated by applications in the geometric modeling of nanotori and the determination of their symmetry groups.

Symmetry Groups Associated with Tilings of a Flat Torus

2014 ◽  
Vol 70 (a1) ◽  
pp. C1428-C1428
Author(s):  
Mark Loyola ◽  
Ma. Louise Antonette De Las Peñas ◽  
Grace Estrada ◽  
Eko Santoso
Keyword(s):  
Symmetry Group ◽  
Full Rank ◽  
Flat Torus ◽  
Space Forms ◽  
Color Symmetry ◽  
Abstract Polytopes ◽  
Symmetry Properties ◽  
Transformation Geometry ◽  
Groups Of Isometries ◽  
Injective Maps

A flat torus E^2/Λ is the quotient of the Euclidean plane E^2 with a full rank lattice Λ generated by two linearly independent vectors v_1 and v_2. A motif-transitive tiling T of the plane whose symmetry group G contains translations with vectors v_1 and v_2 induces a tiling T^* of the flat torus. Using a sequence of injective maps, we realize T^* as a tiling T-of a round torus (the surface of a doughnut) in the Euclidean space E^3. This realization is obtained by embedding T^* into the Clifford torus S^1 × S^1 ⊆ E^4 and then stereographically projecting its image to E^3. We then associate two groups of isometries with the tiling T^* – the symmetry group G^* of T^* itself and the symmetry group G-of its Euclidean realization T-. This work provides a method to compute for G^* and G-using results from the theory of space forms, abstract polytopes, and transformation geometry. Furthermore, we present results on the color symmetry properties of the toroidal tiling T^* in relation with the color symmetry properties of the planar tiling T. As an application, we construct toroidal polyhedra from T-and use these geometric structures to model carbon nanotori and their structural analogs.

Truss and Beam Finite Elements Revisited: A Derivation Based on Displacement-Field Decomposition

1996 ◽  
Vol 11 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Alphose Zingoni
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Symmetry Group ◽  
Displacement Field ◽  
Three Dimensional ◽  
Beam Elements ◽  
Symmetry Properties ◽  
Mass Matrices ◽  
General Displacement

Where a finite element possesses symmetry properties, derivation of fundamental element matrices can be achieved more efficiently by decomposing the general displacement field into subspaces of the symmetry group describing the configuration of the element. In this paper, the procedure is illustrated by reference to the simple truss and beam elements, whose well-known consistent-mass matrices are obtained via the proposed method. However, the procedure is applicable to all one-, two- and three-dimensional finite elements, as long as the shape and node configuration of the element can be described by a specific symmetry group.

Colorings of hyperbolic plane crystallographic patterns

2006 ◽  
Vol 221 (10) ◽  
Author(s):  
Ma. Louise Antonette N. De Las Peñas ◽  
Rene P. Felix ◽  
Glenn R. Laigo
Keyword(s):  
Symmetry Group ◽  
Hyperbolic Plane ◽  
Systematic Approach ◽  
Basic Problem ◽  
Color Symmetry ◽  
Regular Tiling

AbstractIn color symmetry the basic problem has always been to classify symmetrically colored symmetrical patterns [13]. An important step in the study of color symmetry in the hyperbolic plane is the determination of a systematic approach in arriving at colored symmetrical hyperbolic patterns. For a given uncolored semi-regular tiling with symmetry group

scholarly journals PROJECTIVE LINEAR GROUPS AS MAXIMAL SYMMETRY GROUPS

2008 ◽  
Vol 50 (1) ◽  
pp. 83-96 ◽  
Author(s):  
ANNA TORSTENSSON
Keyword(s):  
Symmetry Group ◽  
Hyperbolic Manifold ◽  
Three Dimensional ◽  
Maximal Order ◽  
Linear Groups ◽  
Symmetry Groups ◽  
Maximal Symmetry ◽  
Projective Linear Groups

AbstractA maximal symmetry group is a group of isomorphisms of a three-dimensional hyperbolic manifold of maximal order in relation to the volume of the manifold. In this paper we determine all maximal symmetry groups of the typesPSL(2,q) andPGL(2,q). Depending on the primepthere are one or two such groups withq=pkandkalways equals 1, 2 or 4.

scholarly journals Spatial symmetry groups as sensorimotor guidelines

2008 ◽  
Vol 17 (5-6) ◽  
pp. 347-359
Author(s):  
Gin McCollum
Keyword(s):  
Symmetry Group ◽  
Motor Neurons ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Symmetry Groups ◽  
Coordinate Systems ◽  
Spatial Function ◽  
Logical Structures ◽  
Vestibular Complex ◽  
Causal Logic

While some aspects of neuroanatomical organization are related to packing and access rather than to function, other aspects of anatomical/physiological organization are directly related to function. The mathematics of symmetry groups can be used to determine logical structure in projections and to relate it to function. This paper reviews two studies of the symmetry groups of vestibular projections that are related to the spatial functions of the vestibular complex, including gaze, posture, and movement. These logical structures have been determined by finding symmetry groups of two vestibular projections directly from physiological and anatomical data. Logical structures in vestibular projections are distinct from mapping properties such as the ability to maintain two- and three-dimensional coordinate systems; rather, they provide anatomical/physiological foundations for these mapping properties. The symmetry group of the direct projection from the semicircular canal primary afferents to neck motor neurons is that of the cube (O, the octahedral group), which can serve as a discrete skeleton for coordinate systems in three-dimensional space. The symmetry group of the canal projection from the secondary vestibular afferents to the inferior olive and thence to the cerebellar uvula-nodulus is that of the square (D8), which can support coordinates for the horizontal plane. While the mathematical relationship between these symmetry groups and functions of the vestibular complex are clear, these studies open a larger question: what is the causal logic by which neural centers and their intrinsic organization affect each other and behavior? The relationship of vestibular projection symmetry groups to spatial function make them ideal projections for investigating this causal logic. The symmetry group results are discussed in relationship to possible ways they communicate spatial structure to other neural centers and format spatial functions such as body movements. These two projection symmetry groups suggest that all vestibular projections may have symmetry groups significantly related to function, perhaps all to spatial function.

scholarly journals Designing Color Symmetry in Stigmergic Art

Mathematics ◽  
2021 ◽  
Vol 9 (16) ◽  
pp. 1882
Author(s):  
Hendrik Richter
Keyword(s):  
Symmetry Group ◽  
Design Procedure ◽  
Design Principles ◽  
Generative Art ◽  
Color Symmetry ◽  
Symmetry Properties ◽  
Visual Results

Color symmetry is an extension of the symmetry imposed by isometric transformations and indicates that the colors of geometrical objects are assigned according to the symmetry properties of these objects. A color symmetry permutes the coloring of the objects consistently with their symmetry group. We apply this concept to bio-inspired generative art. Therefore, the geometrical objects are interpreted as motifs that may repeat themselves with a symmetry-consistent coloring. The motifs are obtained by design principles from stigmergy. We discuss the design procedure and present visual results.

Color groups arising from index-nsubgroups of symmetry groups

2015 ◽  
Vol 71 (2) ◽  
pp. 216-224 ◽  
Author(s):  
René P. Felix ◽  
Allan O. Junio
Keyword(s):  
Symmetry Group ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
The Other ◽  
Symmetry Groups ◽  
Color Group ◽  
Color Symmetry ◽  
Intermediate Subgroup ◽  
Symmetrical Object ◽  
Necessary And Sufficient

One of the main goals in the study of color symmetry is to classify colorings of symmetrical objects through their color groups. The term color group is taken to mean the subgroup of the symmetry group of the uncolored symmetrical object which induces a permutation of colors in the coloring. This work looks for methods of determining the color group of a colored symmetric object. It begins with an indexnsubgroupHof the symmetry groupGof the uncolored object. It then considersH-invariant colorings of the object, so that the color groupH*will be a subgroup ofGcontainingH. In other words,H≤H*≤G. It proceeds to give necessary and sufficient conditions for the equality ofH*andG. IfH*≠Gandnis prime, thenH*=H. On the other hand, ifH*≠Gandnis not prime, methods are discussed to determine whetherH*isG,Hor some intermediate subgroup betweenHandG.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Semi-automated methods for 3-D reconstruction of macromolecular complexes

1995 ◽  
Vol 53 ◽  
pp. 42-43
Author(s):  
B. Carragher ◽  
M. Whittaker
Keyword(s):  
Three Dimensional ◽  
Time Saving ◽  
Macromolecular Complexes ◽  
Symmetry Properties ◽  
Dimensional Reconstruction ◽  
Experienced Operator ◽  
Projection Images ◽  
The Individual ◽  
Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

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