Simple Structures with Complex Symmetry
نویسندگان
چکیده
We define the automorphism spectrum of a computable structure M, a measurement of the complexity of the symmetries of M, and prove that certain sets of Turing degrees can be realized as automorphism spectra, while certain others cannot.
منابع مشابه
The Effect of Textual Enhancement Types on EFL Learners’ Grammatical Awareness of Simple and Complex Structures
The purpose of this study was to investigate the effect of textual enhancement types on English as Foreign Language ( EFL ) learn er s ’ grammatical awareness of simple and complex structures. A nu m- ber of 104 learners from Ayandegan Institute, in Tehran, participated in this study. To homogenize the samples, the researchers administered a placement Michigan Test of English language to the p...
متن کاملOn Symmetry of Some Nano Structures
It is necessary to generate the automorphism group of a chemical graph in computer-aided structure elucidation. An Euclidean graph associated with a molecule is defined by a weighted graph with adjacency matrix M = [dij], where for i≠j, dij is the Euclidean distance between the nuclei i and j. In this matrix dii can be taken as zero if all the nuclei are equivalent. Otherwise, one may introduce...
متن کاملCalculation of Buckling Load and Eigen Frequencies for Planar Truss Structures with Multi-Symmetry
In this paper, the region in which the structural system is situated is divided into four subregions, namely upper, lower, left and right subregions. The stiffness matrix of the entire system is then formed and using the existing direct symmetry and reverse symmetry, the relationships between the entries of the matrix are established. Examples are included to illustrate the steps of the method.
متن کاملBreakthrough in the high-pressure structures of Ba based on full exploitation of aperiodic symmetry
A breakthrough in the high-pressure structures of Ba based on a full exploitation of aperiodic symmetry is discussed in the general context of the 'complex structures of simple metals'.
متن کاملA Computational Study to Find the Vibrational Modes Connected with Specific Molecular Structures of Calculated Compound
The purpose of this research is to provide a deeper understanding of the planar high- symmetry configuration instability. In the ideal case, the distortion corresponds to the movements of nuclei along normal modes that belong to non-totally symmetric irreps of the high symmertry (HS) point group of molecule. The analysis of the structural distortion from the HS nuclear arrangements of the JT ac...
متن کاملThe Index-Based Subgraph Matching Algorithm with General Symmetries (ISMAGS): Exploiting Symmetry for Faster Subgraph Enumeration
Subgraph matching algorithms are used to find and enumerate specific interconnection structures in networks. By enumerating these specific structures/subgraphs, the fundamental properties of the network can be derived. More specifically in biological networks, subgraph matching algorithms are used to discover network motifs, specific patterns occurring more often than expected by chance. Findin...
متن کامل