Results 11 to 20 of about 290 (150)

Cayley hypergraph over polygroups [PDF]

Transactions on Combinatorics
Comer introduced a class of hypergroups, using the name of polygroups. He emphasized the importance of polygroups, by analyzing them in connections to graphs, relations, Boolean and cylindric algebras.
Abolfazl Nikkhah, Bijan Davvaz
doaj   +1 more source

Representability is not decidable for finite relation algebras [PDF]

, 2001
Published ...
Hirsch, R, Hodkinson, I
core   +1 more source

Relation algebras from cylindric algebras, II

Annals of Pure and Applied Logic, 2001
For every \(n\geq 3\), \(\mathbf{S}\mathcal RaCA_n\) is, by definition, the class of subalgebras of relation-algebraic reducts of cylindric algebras of dimension \(n\). It was known that \(\mathbf{S}\mathcal RaCA_4\) is the class of relation algebras, and that, for every \(n\geq 4\), \(\mathbf{S}\mathcal RaCA_n\) is a canonical variety, that is, it is ...
Robin Hirsch, Ian M. Hodkinson
openaire   +4 more sources

Regular cylindrical algebraic decomposition [PDF]

Journal of the London Mathematical Society, 2019
We show that a strong well-based cylindrical algebraic decomposition P of a bounded semi-algebraic set is a regular cell decomposition, in any dimension and independently of the method by which P is constructed. Being well-based is a global condition on P that holds for the output of many widely used algorithms. We also show the same for S of dimension
Davenport, James, Locatelli, Acyr, Sankaran, Gregory   +2 more
openaire   +3 more sources

Axiomatizing complex algebras by games [PDF]

, 2001
Submitted ...
Mikulas, S, Hodkinson, I, Venema, Y, Hodkinson, I., Mikulás, Sz., Venema, Y.   +5 more
core   +1 more source

Cylindrical algebraic decomposition with equational constraints [PDF]

Journal of Symbolic Computation, 2020
Accepted into the Journal of Symbolic Computation.
Matthew England 0001, Russell J. Bradford, James H. Davenport   +2 more
openaire   +3 more sources

Lifting Results for Finite Dimensions to the Transfinite in Systems of Varieties Using Ultraproducts

Bulletin of the Section of Logic
We redefine a system of varieties definable by a schema of equations to include finite dimensions. Then we present a technique using ultraproducts enabling one to lift results proved for every finite dimension to the transfinite.
Tarek Sayed Ahmed
doaj   +1 more source

Cylindrical algebraic decompositions for boolean combinations [PDF]

Proceedings of the 38th International Symposium on Symbolic and Algebraic Computation, 2013
This article makes the key observation that when using cylindrical algebraic decomposition (CAD) to solve a problem with respect to a set of polynomials, it is not always the signs of those polynomials that are of paramount importance but rather the truth values of certain quantifier free formulae involving them.
Russell J. Bradford, James H. Davenport, Matthew England 0001, Scott McCallum, David J. Wilson   +4 more
openaire   +2 more sources

Canonical varieties with no canonical axiomatisation [PDF]

, 2005
Accepted ...
Yde Venema, Ian Hodkinson, Hodkinson, I, Venema, Y, Hodkinson, I., Venema, Y.   +5 more
core   +1 more source

Beyond Percolation: Graphene‐Enabled Network Reinforcement Enhances Thermal Transport in Paraffin Phase‐Change Composites

Advanced Science, EarlyView.
Expanded‐graphite/graphene‐nanoplatelet hybrids deliver a near‐order‐of‐magnitude thermal‐conductivity enhancement in paraffin phase‐change materials. A microCT‐informed 3D modeling framework resolves the percolating EG backbone and captures sub‐voxel GNP enrichment, quantitatively linking microstructure to heat flow and revealing a graphene‐enabled ...
Thomas Hoke, Jackson Hoke, Shucheng Guo, Brittany Chan, Xi Chen   +4 more
wiley   +1 more source