Results 11 to 20 of about 102 (99)
Finiteness theorems on elliptical billiards and a variant of the dynamical Mordell–Lang conjecture
Abstract We offer some theorems, mainly finiteness results, for certain patterns in elliptical billiards, related to periodic trajectories; these seem to be the first finiteness results in this context. For instance, if two players hit a ball at a given position and with directions forming a fixed angle in (0,π)$(0,\pi )$, there are only finitely many ...
Pietro Corvaja, Umberto Zannier
wiley +1 more source
Associahedra for finite‐type cluster algebras and minimal relations between g‐vectors
Abstract We show that the mesh mutations are the minimal relations among the g${\bm{g}}$‐vectors with respect to any initial seed in any finite‐type cluster algebra. We then use this algebraic result to derive geometric properties of the g${\bm{g}}$‐vector fan: we show that the space of all its polytopal realizations is a simplicial cone, and we then ...
Arnau Padrol +3 more
wiley +1 more source
On fractional semidiscrete Dirac operators of Lévy–Leblond type
Abstract In this paper, we introduce a wide class of space‐fractional and time‐fractional semidiscrete Dirac operators of Lévy–Leblond type on the semidiscrete space‐time lattice hZn×[0,∞)$h{\mathbb {Z}}^n\times [0,\infty )$ (h>0$h>0$), resembling to fractional semidiscrete counterparts of the so‐called parabolic Dirac operators.
Nelson Faustino
wiley +1 more source
Endomorphism semigroups and lightlike translations [PDF]
16 pages, Latex; minor ...
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A CHARACTERIZATION OF SCHMIDT GROUPS BY THEIR ENDOMORPHISM SEMIGROUPS [PDF]
A Schmidt group is a non-nilpotent finite group in which each proper subgroup is nilpotent. Each Schmidt group G is a solvable group of order ps qv (where p and q are different primes) with a unique Sylow p-subgroup P and a cyclic Sylow q-subgroup Q, and hence G is a semidirect product of P by Q.
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On semigroups of endomorphisms of a chain with restricted range [PDF]
Let $X$ be a finite or infinite chain and let $O(X)$ be the monoid of all endomorphisms of $X$. In this paper, we describe the largest regular subsemigroup of $O(X)$ and Green's relations on $O(X)$. In fact, more generally, if $Y$ is a nonempty subset of $X$ and $O(X,Y)$ the subsemigroup of $O(X)$ of all elements with range contained in $Y$, we ...
Fernandes, Vitor H. +3 more
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Semigroup endomorphisms of rings [PDF]
AbstractWe show that rings for which every non-constant multiplicative endomorphism is additive are trivial or power rings (that is, rings R such that R = R2 and x2 = 0 = x+x for all x ∈ R) and that if R is a power ring for which every multiplicative endomorphism is additive, then End (R) is a zero semigroup or a semilattice according to how the ...
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Throughout this paper our study focuses on transformation semigroups. These kinds of semigroups are the corner stone of semigroup theory. This is because every semigroup is isomorphic to transformation semigroup.
Asawer Al-Aadhami, Hala M. Sulaiman
doaj +1 more source
On the theories classified by an étendue
Abstract We give a model‐theoretic characterisation of the geometric theories classified by étendues—the ‘locally localic’ topoi. They are the theories where each model is determined, syntactically and semantically, by any witness of a fixed collection of formulae.
Joshua L. Wrigley
wiley +1 more source
Endomorphisms of Finite Symmetric Inverse Semigroups
Denote by \({\mathcal I}_n\) the symmetric inverse semigroup on \(X=\{1,2,\dots,n\}\). For any function \(f\), the rank of \(f\) is denoted by \(\text{rank}(f)\) and is the cardinality of the range of \(f\). For \(1\leq k\leq n+1\), let \(I_k=\{t\in{\mathcal I}_n:\text{rank}(t)2\) and \(n\neq 4\). If \(\varphi\) is an endomorphism of \({\mathcal I}_n\)
Schein, Boris M., Teclezghi, Beimnet
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