121 research outputs found
Generalizations of the Muller-Schupp theorem and tree-like inverse graphs
We extend the characterization of context-free groups of Muller and Schupp in
two ways. We first show that for a quasi-transitive inverse graph ,
being quasi-isometric to a tree, or context-free (finitely many end-cones
types), or having the automorphism group that is virtually free,
are all equivalent conditions. Furthermore, we add to the previous equivalences
a group theoretic analog to the representation theorem of
Chomsky-Sch\"utzenberger that is fundamental in solving a weaker version of a
conjecture of T. Brough which also extends Muller and Schupp' result to the
class of groups that are virtually finitely generated subgroups of direct
product of free groups. We show that such groups are precisely those whose word
problem is the intersection of a finite number of languages accepted by
quasi-transitive, tree-like inverse graphs
Undecidability and novelty generation in RNA automata
As today, the evolution of the earliest life was an exploration of adaptive forms. The earliest life also undertook great leaps in the overall complexity of the molecular dynamic system. A theoretical framework for this form of evolution has not been resolved. This thesis builds upon the discoveries of early life chemistry and seeks to move towards understanding the organising principles that allowed life to evolve. In computer science novelty generation is often linked to universal computation, as the boundaries of complexity are found at the edge of undecidability where self-referential incomputable statements can be generated.
At the intersection of early life chemistry and computer science, this thesis draws from the dominant RNA-world model and incorporates this into the constructions of automata theory to investigate the computational properties of a system of single-stranded RNA molecules. Limited to the plausible RNA-world operations of ligation and cleavage, RNA automata are constructed of increasing complexity; from the Finite Automaton (RNA-FA) to the Turing machine equivalent 2-stack Pushdown Automaton (RNA-2PDA) and ultimately a universal RNA-UPDA with the capacity to generate undecidability. A path forward from undecidable computation in RNA automata to novelty generation is mapped. The coupled phenotype-environment space is presented as a framework for biological system expansion. The framework draws on the discoveries of Alan Turing and Emil Post on the continual expansion of computational systems overcoming their undecidable boundaries. An analogue of these extensions, from the perspective of ecological developmental biology, offers a self-referential model of the organism coupled with its environment, which is capable of novelty generation. This thesis concludes by outlining future avenues of research to develop the coupled phenotype-environment space framework as well as identifying biological computational constructions in extant organisms
Review of Particle Physics
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,143
new measurements from 709 papers, we list, evaluate, and average measured properties of gauge bosons and the
recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical
particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search
limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs
Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology,
Particle Detectors, Colliders, Probability and Statistics. Among the 120 reviews are many that are new or heavily
revised, including a new review on Machine Learning, and one on Spectroscopy of Light Meson Resonances.
The Review is divided into two volumes. Volume 1 includes the Summary Tables and 97 review articles. Volume
2 consists of the Particle Listings and contains also 23 reviews that address specific aspects of the data presented
in the Listings.
The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov)
and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary
Tables and essential tables, figures, and equations from selected review articles is available in print, as a web version
optimized for use on phones, and as an Android app.United States Department of Energy (DOE) DE-AC02-05CH11231government of Japan (Ministry of Education, Culture, Sports, Science and Technology)Istituto Nazionale di Fisica Nucleare (INFN)Physical Society of Japan (JPS)European Laboratory for Particle Physics (CERN)United States Department of Energy (DOE
Equilibrium and dynamical computation schemes for vibronic models of nonadiabatic systems
Two computational schemes were investigated for studying vibronic models of nonadiabatic systems: Path Integral Monte Carlo (PIMC) and vibrational electronic coupled cluster (VECC).
A PIMC method was used to investigate the distributions of normal modes of nonadiabatic systems. The key element to this approach is the use of gaussian mixture distributions (GMD), and the evaluation of the path integral through matrix products instead of individual matrix elements. By using PIMC with a GMD-reduced scheme, we showed that it is possible to circumvent a sign-problem presented by the non-stoquastic nature of the vibronic Hamiltonian. An alternative GMD scheme was shown to be effective for systems with weaker coupling when the vibronic Hamiltonian is not non-stoquastic.
In recent years a new approach, VECC, was developed, in the Nooijen group by the graduate student Songhao Bao, to describe electronic absorption spectra. The problem of determining detailed equations of motion (EOM) used in VECC was solved and implemented in a software package named termfactory. We explored a variety of ways to represent the constraints of the equations of motion for further generalization of termfactory. A particular realization of these EOM were developed and applied to produce vibrationally-resolved electronic spectra from auto-correlation functions (ACFs) by way of real-time propagation of a coupled cluster (CC) wave function whose operators are expressed in the second quantized formulation.
Our implementation, called t-amplitudes, showed excellent agreement with Multi-configuration time-dependent Hartree (MCTDH) for small molecules, but with much improved computational runtimes. For a larger system, hexahelicene, we were able to replicate the overall shape of the spectra as presented in the literature
Proceedings of the 22nd Conference on Formal Methods in Computer-Aided Design – FMCAD 2022
The Conference on Formal Methods in Computer-Aided Design (FMCAD) is an annual conference on the theory and applications of formal methods in hardware and system verification. FMCAD provides a leading forum to researchers in academia and industry for presenting and discussing groundbreaking methods, technologies, theoretical results, and tools for reasoning formally about computing systems. FMCAD covers formal aspects of computer-aided system design including verification, specification, synthesis, and testing
Foundations of Software Science and Computation Structures
This open access book constitutes the proceedings of the 25th International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2022, which was held during April 4-6, 2022, in Munich, Germany, as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2022. The 23 regular papers presented in this volume were carefully reviewed and selected from 77 submissions. They deal with research on theories and methods to support the analysis, integration, synthesis, transformation, and verification of programs and software systems
Weighted Tree Automata -- May it be a little more?
This is a book on weighted tree automata. We present the basic definitions
and some of the important results in a coherent form with full proofs. The
concept of weighted tree automata is part of Automata Theory and it touches the
area of Universal Algebra. It originated from two sources: weighted string
automata and finite-state tree automata
Atherosclerosis: Methods and Protocols
This volume provides detailed, up-to-date methods used in research on Atherosclerosis. Chapters guide readers through an overview of the pathogenesis of atherosclerosis and model systems together with in vitro, ex vivo, in vivo and emerging methods in atherosclerosis research. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls.
Authoritative and cutting-edge, Atherosclerosis: Methods and Protocols serves as an invaluable resource for those engaging in research on atherosclerosis and cardiovascular disease, as well as for researchers who are new to t
Review of Particle Physics
The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,143 new measurements from 709 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 120 reviews are many that are new or heavily revised, including a new review on Machine Learning, and one on Spectroscopy of Light Meson Resonances.
The Review is divided into two volumes. Volume 1 includes the Summary Tables and 97 review articles. Volume 2 consists of the Particle Listings and contains also 23 reviews that address specific aspects of the data presented in the Listings.
The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print, as a web version optimized for use on phones, and as an Android app
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