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Displaying similar documents to “Torsion points on curves and common divisors of a k - 1 and b k - 1

On the torsion of the Jacobians of the hyperelliptic curves y² = xⁿ + a and y² = x(xⁿ+a)

Tomasz Jędrzejak (2016)

Acta Arithmetica

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Consider two families of hyperelliptic curves (over ℚ), C n , a : y ² = x + a and C n , a : y ² = x ( x + a ) , and their respective Jacobians J n , a , J n , a . We give a partial characterization of the torsion part of J n , a ( ) and J n , a ( ) . More precisely, we show that the only prime factors of the orders of such groups are 2 and prime divisors of n (we also give upper bounds for the exponents). Moreover, we give a complete description of the torsion part of J 8 , a ( ) . Namely, we show that J 8 , a ( ) t o r s = J 8 , a ( ) [ 2 ] . In addition, we characterize the torsion parts of J p , a ( ) , where p is an odd...

Characterization of the torsion of the Jacobians of two families of hyperelliptic curves

Tomasz Jędrzejak (2013)

Acta Arithmetica

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Consider the families of curves C n , A : y ² = x + A x and C n , A : y ² = x + A where A is a nonzero rational. Let J n , A and J n , A denote their respective Jacobian varieties. The torsion points of C 3 , A ( ) and C 3 , A ( ) are well known. We show that for any nonzero rational A the torsion subgroup of J 7 , A ( ) is a 2-group, and for A ≠ 4a⁴,-1728,-1259712 this subgroup is equal to J 7 , A ( ) [ 2 ] (for a excluded values of A, with the possible exception of A = -1728, this group has a point of order 4). This is a variant of the corresponding results for J 3 , A (A ≠ 4) and J 5 , A . We...

Circulant matrices with orthogonal rows and off-diagonal entries of absolute value 1

Daniel Uzcátegui Contreras, Dardo Goyeneche, Ondřej Turek, Zuzana Václavíková (2021)

Communications in Mathematics

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It is known that a real symmetric circulant matrix with diagonal entries d 0 , off-diagonal entries ± 1 and orthogonal rows exists only of order 2 d + 2 (and trivially of order 1 ) [Turek and Goyeneche 2019]. In this paper we consider a complex Hermitian analogy of those matrices. That is, we study the existence and construction of Hermitian circulant matrices having orthogonal rows, diagonal entries d 0 and any complex entries of absolute value 1 off the diagonal. As a particular case, we consider...

Controllable and tolerable generalized eigenvectors of interval max-plus matrices

Matej Gazda, Ján Plavka (2021)

Kybernetika

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By max-plus algebra we mean the set of reals equipped with the operations a b = max { a , b } and a b = a + b for a , b . A vector x is said to be a generalized eigenvector of max-plus matrices A , B ( m , n ) if A x = λ B x for some λ . The investigation of properties of generalized eigenvectors is important for the applications. The values of vector or matrix inputs in practice are usually not exact numbers and they can be rather considered as values in some intervals. In this paper the properties of matrices and vectors with inexact (interval)...

-simplicity of interval max-min matrices

Ján Plavka, Štefan Berežný (2018)

Kybernetika

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A matrix A is said to have 𝐗 -simple image eigenspace if any eigenvector x belonging to the interval 𝐗 = { x : x ̲ x x ¯ } containing a constant vector is the unique solution of the system A y = x in 𝐗 . The main result of this paper is an extension of 𝐗 -simplicity to interval max-min matrix 𝐀 = { A : A ̲ A A ¯ } distinguishing two possibilities, that at least one matrix or all matrices from a given interval have 𝐗 -simple image eigenspace. 𝐗 -simplicity of interval matrices in max-min algebra are studied and equivalent conditions for...

The space S α , β and σ-core

Bruno de Malafosse (2006)

Studia Mathematica

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We give some new properties of the space S α , β and we apply them to the σ-core theory. These results generalize those by Choudhary and Yardimci.

Linear preservers of rc-majorization on matrices

Mohammad Soleymani (2024)

Czechoslovak Mathematical Journal

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Let A , B be n × m matrices. The concept of matrix majorization means the j th column of A is majorized by the j th column of B and this is done for all j by a doubly stochastic matrix D . We define rc-majorization that extended matrix majorization to columns and rows of matrices. Also, the linear preservers of rc-majorization will be characterized.

G-matrices, J -orthogonal matrices, and their sign patterns

Frank J. Hall, Miroslav Rozložník (2016)

Czechoslovak Mathematical Journal

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A real matrix A is a G-matrix if A is nonsingular and there exist nonsingular diagonal matrices D 1 and D 2 such that A - T = D 1 A D 2 , where A - T denotes the transpose of the inverse of A . Denote by J = diag ( ± 1 ) a diagonal (signature) matrix, each of whose diagonal entries is + 1 or - 1 . A nonsingular real matrix Q is called J -orthogonal if Q T J Q = J . Many connections are established between these matrices. In particular, a matrix A is a G-matrix if and only if A is diagonally (with positive diagonals) equivalent to a column permutation...

A note on the torsion of the Jacobians of superelliptic curves y q = x p + a

Tomasz Jędrzejak (2016)

Banach Center Publications

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This article is a short version of the paper published in J. Number Theory 145 (2014) but we add new results and a brief discussion about the Torsion Conjecture. Consider the family of superelliptic curves (over ℚ) C q , p , a : y q = x p + a , and its Jacobians J q , p , a , where 2 < q < p are primes. We give the full (resp. partial) characterization of the torsion part of J 3 , 5 , a ( ) (resp. J q , p , a ( ) ). The main tools are computations of the zeta function of C 3 , 5 , a (resp. C q , p , a ) over l for primes l ≡ 1,2,4,8,11 (mod 15) (resp. for primes l...

Maps on upper triangular matrices preserving zero products

Roksana Słowik (2017)

Czechoslovak Mathematical Journal

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Consider 𝒯 n ( F ) —the ring of all n × n upper triangular matrices defined over some field F . A map φ is called a zero product preserver on 𝒯 n ( F ) in both directions if for all x , y 𝒯 n ( F ) the condition x y = 0 is satisfied if and only if φ ( x ) φ ( y ) = 0 . In the present paper such maps are investigated. The full description of bijective zero product preservers is given. Namely, on the set of the matrices that are invertible, the map φ may act in any bijective way, whereas for the zero divisors and zero matrix one can write φ as a...

( 0 , 1 ) -matrices, discrepancy and preservers

LeRoy B. Beasley (2019)

Czechoslovak Mathematical Journal

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Let m and n be positive integers, and let R = ( r 1 , ... , r m ) and S = ( s 1 , ... , s n ) be nonnegative integral vectors. Let A ( R , S ) be the set of all m × n ( 0 , 1 ) -matrices with row sum vector R and column vector S . Let R and S be nonincreasing, and let F ( R ) be the m × n ( 0 , 1 ) -matrix, where for each i , the i th row of F ( R , S ) consists of r i 1’s followed by ( n - r i ) 0’s. Let A A ( R , S ) . The discrepancy of A, disc ( A ) , is the number of positions in which F ( R ) has a 1 and A has a 0. In this paper we investigate linear operators mapping m × n matrices over...

On a sum involving the integral part function

Bo Chen (2024)

Czechoslovak Mathematical Journal

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Let [ t ] be the integral part of a real number t , and let f be the arithmetic function satisfying some simple condition. We establish a new asymptotical formula for the sum S f ( x ) = n x f ( [ x / n ] ) , which improves the recent result of J. Stucky (2022).

A computation of positive one-peak posets that are Tits-sincere

Marcin Gąsiorek, Daniel Simson (2012)

Colloquium Mathematicae

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A complete list of positive Tits-sincere one-peak posets is provided by applying combinatorial algorithms and computer calculations using Maple and Python. The problem whether any square integer matrix A ( ) is ℤ-congruent to its transpose A t r is also discussed. An affirmative answer is given for the incidence matrices C I and the Tits matrices C ̂ I of positive one-peak posets I.