Results 81 to 90 of about 53,514 (278)

Rational points in a family of conics over F2(t)$\mathbb {F}_2(t)$

open access: yesMathematische Nachrichten, EarlyView.
Abstract Serre famously showed that almost all plane conics over Q$\mathbb {Q}$ have no rational point. We investigate versions of this over global function fields, focusing on a specific family of conics over F2(t)$\mathbb {F}_2(t)$ which illustrates new behavior.
Daniel Loughran, Judith Ortmann
wiley   +1 more source

Attribute Implication Bases From Galois Connection Structures

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT Modeling knowledge systems by determining relationships among key variables have been and currently is a fundamental and nontrivial challenge in real‐world scenarios. Many approaches have been developed to reach this goal, but many of them are heuristic and require of alternative procedures to provide robust and tractable rules.
M. Eugenia Cornejo   +2 more
wiley   +1 more source

Methodology for Modeling Coupled Rigid Multibody Systems Using Unitary Quaternions: The Case of Planar RRR and Spatial PRRS Parallel Robots

open access: yesRobotics
Quaternions are used in various applications, especially in those where it is necessary to model and represent rotational movements, both in the plane and in space, such as in the modeling of the movements of robots and mechanisms.
Francisco Cuenca Jiménez   +5 more
doaj   +1 more source

Automated Symbolic and Numerical Testing of DLMF Formulae Using Computer Algebra Systems [PDF]

open access: yes, 2018
We have developed an automated procedure for symbolic and numerical testing of formulae extracted from the NIST Digital Library of Mathematical Functions (DLMF). For the NIST Digital Repository of Mathematical Formulae, we have developed conversion tools from semantic LaTeX to the Computer Algebra System (CAS) Maple which relies on Youssef's part-of ...
Cohl, Howard S.   +2 more
openaire   +2 more sources

Computer algebra and operators [PDF]

open access: yes
The symbolic computation of operator expansions is discussed. Some of the capabilities that prove useful when performing computer algebra computations involving operators are considered.
Fateman, Richard, Grossman, Robert
core   +1 more source

Interaction of Dirac δ$$ \delta $$‐Waves in the Inviscid Levine and Sleeman Chemotaxis Model

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT This article investigates interactions of δ$$ \delta $$‐shock waves in the inviscid Levine and Sleeman chemotaxis model ut−λ(uv)x=0$$ {u}_t-\lambda {(uv)}_x=0 $$, vt−ux=0$$ {v}_t-{u}_x=0 $$. The analysis employs a distributional product and a solution concept that extends the classical solution concept.
Adelino Paiva
wiley   +1 more source

Repeatability of Rapid Human Cardiac Phosphorus MRSI (31P‐MRSI) Using Concentric Ring Trajectory Readouts at 7 T

open access: yesMagnetic Resonance in Medicine, EarlyView.
ABSTRACT Purpose PCr/ATP ratio is determined at 7 T typically using Fourier‐transform based magnetic resonance spectroscopic imaging sequences (FT‐MRSI). These sequences require acquisition times longer than desirable for inclusion in cardiac clinical trials. Concentric ring trajectory (CRT‐MRSI) has been described as an accelerated alternative k‐space
Ferenc E. Mózes   +8 more
wiley   +1 more source

Computational linear algebra over finite fields [PDF]

open access: yes, 2012
We present here algorithms for efficient computation of linear algebra problems over finite ...
Dumas, Jean-Guillaume, Pernet, Clément
core   +3 more sources

Robustness Assessment of Public Transport Networks in Various Graph Representations: Systematic Review, Decision Support, and Case Study

open access: yesNetworks, EarlyView.
ABSTRACT The analysis of certain properties of the underlying graph of a public transport network generates insights about the network's structure. Hereby, the choice of the graph representation depends on a trade‐off between complexity reduction and information preservation to adequately model a public transport network.
Michael Palk   +2 more
wiley   +1 more source

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