We compute rational points on real hyperelliptic curves of genus 3 defined on <img src="Edit_ff1a2758-8302-45a6-8c7e-a73bd35f12bd.png" width="20" height="18" alt="" /> who...We compute rational points on real hyperelliptic curves of genus 3 defined on <img src="Edit_ff1a2758-8302-45a6-8c7e-a73bd35f12bd.png" width="20" height="18" alt="" /> whose Jacobian have Mordell-Weil rank <em>r=0</em>. We present an implementation in sagemath of an algorithm which describes the birational transformation of real hyperelliptic curves into imaginary hyperelliptic curves and <span>the Chabauty-Coleman method to find <em>C </em>(<img src="Edit_243e29b4-1b26-469a-9e65-461ffac1e473.png" width="20" height="18" alt="" />)<span></span>. We run the algorithms in</span> Sage on 47 real hyperelliptic curves of genus 3.展开更多
We study the classification of elliptic curves E over the rationals Q according to the torsion subgroups E_(tors)(Q). More precisely, we classify those elliptic curves with E_(tors)(Q) being cyclic with even orders. W...We study the classification of elliptic curves E over the rationals Q according to the torsion subgroups E_(tors)(Q). More precisely, we classify those elliptic curves with E_(tors)(Q) being cyclic with even orders. We also give explicit formulas for generators of E_(tors)(Q). These results, together with the recent results of K. Ono for the non-cyclic E_(tors)(Q), completely solve the problem of the explicit classification and parameterization when E has a rational point of order 2.展开更多
We classify,up to some lattice-theoretic equivalence,all possible configurations of rational double points that can appear on a surface whose minimal resolution is a complex Enriques surface.
Let Fqbe the finite field,q=p^(k),with p being a prime and k being a positive integer.Let F_(q)^(*)be the multiplicative group of Fq,that is F_(q)^(*)=F_(q){0}.In this paper,by using the Jacobi sums and an analog of H...Let Fqbe the finite field,q=p^(k),with p being a prime and k being a positive integer.Let F_(q)^(*)be the multiplicative group of Fq,that is F_(q)^(*)=F_(q){0}.In this paper,by using the Jacobi sums and an analog of Hasse-Davenport theorem,an explicit formula for the number of solutions of cubic diagonal equation x_(1)^(3)+x_(2)^(3)+…+x_(n)^(3)=c over Fqis given,where c∈F_(q)^(*)and p≡1(mod 3).This extends earlier results.展开更多
Let s be a positive integer,p be an odd prime,q=p^(s),and let F_(q)be a finite field of q elements.Let N_(q)be the number of solutions of the following equations:(x_(1)^(m_(1))+x_(2)^(m_(2))+…+x_(n)^(m_(n)))^(k)=x_(1...Let s be a positive integer,p be an odd prime,q=p^(s),and let F_(q)be a finite field of q elements.Let N_(q)be the number of solutions of the following equations:(x_(1)^(m_(1))+x_(2)^(m_(2))+…+x_(n)^(m_(n)))^(k)=x_(1)x_(2)…x_(n)x^(k_(n+1))_(n+1)…x^(k_(t))_(t)over the finite field F_(q),with n≥2,t>n,k,and k_(j)(n+1≤j≤t),m_(i)(1≤i≤n)are positive integers.In this paper,we find formulas for N_(q)when there is a positive integer l such that dD|(p^(l)+1),where D=1 cm[d_(1),…,d_(n)],d=gcd(n∑i=1M/m_(i)-kM,(q-1)/D),M=1 cm[m_(1),…,m_(n)],d_(j)=gcd(m_(j),q-1),1≤j≤n.And we determine N_(q)explicitly under certain cases.This extends Markoff-Hurwitz-type equations over finite field.展开更多
Let Fq stand for the finite field of odd characteristic p with q elements(q=pn,n∈N)and Fq* denote the set of all the nonzero elements of Fq.In this paper,by using the augmented degree matrix and the result given b...Let Fq stand for the finite field of odd characteristic p with q elements(q=pn,n∈N)and Fq* denote the set of all the nonzero elements of Fq.In this paper,by using the augmented degree matrix and the result given by Cao,we obtain a formula for the number of rational points of the following equation over Fq:f(x 1,x 2,...,x n)=(a1 x1 x2d+a2 x2 x3d...+a(n-1)x(n-1)xnd+an xn x1d)λ-bx1(d1)x2d2...xn(dn),with ai,b∈Fq*,n≥2,λ〉0 being positive integers,and d,di being nonnegative integers for 1≤i n.This technique can be applied to the polynomials of the form h1λ=h2 with λ being positive integer and h1,h2∈Fq[x 1,x 2,...,x n].It extends the results of the Markoff-Hurwitz-type equations.展开更多
文摘We compute rational points on real hyperelliptic curves of genus 3 defined on <img src="Edit_ff1a2758-8302-45a6-8c7e-a73bd35f12bd.png" width="20" height="18" alt="" /> whose Jacobian have Mordell-Weil rank <em>r=0</em>. We present an implementation in sagemath of an algorithm which describes the birational transformation of real hyperelliptic curves into imaginary hyperelliptic curves and <span>the Chabauty-Coleman method to find <em>C </em>(<img src="Edit_243e29b4-1b26-469a-9e65-461ffac1e473.png" width="20" height="18" alt="" />)<span></span>. We run the algorithms in</span> Sage on 47 real hyperelliptic curves of genus 3.
基金Project supported by the National Natural Science Foundation of China (Grant No. 19771052)
文摘We study the classification of elliptic curves E over the rationals Q according to the torsion subgroups E_(tors)(Q). More precisely, we classify those elliptic curves with E_(tors)(Q) being cyclic with even orders. We also give explicit formulas for generators of E_(tors)(Q). These results, together with the recent results of K. Ono for the non-cyclic E_(tors)(Q), completely solve the problem of the explicit classification and parameterization when E has a rational point of order 2.
文摘We classify,up to some lattice-theoretic equivalence,all possible configurations of rational double points that can appear on a surface whose minimal resolution is a complex Enriques surface.
基金Supported by the Natural Science Foundation of Henan Province(232300420123)the National Natural Science Foundation of China(12026224)the Research Center of Mathematics and Applied Mathematics,Nanyang Institute of Technology。
文摘Let Fqbe the finite field,q=p^(k),with p being a prime and k being a positive integer.Let F_(q)^(*)be the multiplicative group of Fq,that is F_(q)^(*)=F_(q){0}.In this paper,by using the Jacobi sums and an analog of Hasse-Davenport theorem,an explicit formula for the number of solutions of cubic diagonal equation x_(1)^(3)+x_(2)^(3)+…+x_(n)^(3)=c over Fqis given,where c∈F_(q)^(*)and p≡1(mod 3).This extends earlier results.
基金Supported by the National Natural Science Foundation of China(12026224)
文摘Let s be a positive integer,p be an odd prime,q=p^(s),and let F_(q)be a finite field of q elements.Let N_(q)be the number of solutions of the following equations:(x_(1)^(m_(1))+x_(2)^(m_(2))+…+x_(n)^(m_(n)))^(k)=x_(1)x_(2)…x_(n)x^(k_(n+1))_(n+1)…x^(k_(t))_(t)over the finite field F_(q),with n≥2,t>n,k,and k_(j)(n+1≤j≤t),m_(i)(1≤i≤n)are positive integers.In this paper,we find formulas for N_(q)when there is a positive integer l such that dD|(p^(l)+1),where D=1 cm[d_(1),…,d_(n)],d=gcd(n∑i=1M/m_(i)-kM,(q-1)/D),M=1 cm[m_(1),…,m_(n)],d_(j)=gcd(m_(j),q-1),1≤j≤n.And we determine N_(q)explicitly under certain cases.This extends Markoff-Hurwitz-type equations over finite field.
基金Supported partially by the Key Program of Universities of Henan Province(17A110010)Science and Technology Department of Henan Province(152300410180,142300410107,182102210379)+1 种基金China Postdoctoral Science Foundation Funded Project(2016M602251)the National Natural Science Foundation of China(11501387,U1504105)
文摘Let Fq stand for the finite field of odd characteristic p with q elements(q=pn,n∈N)and Fq* denote the set of all the nonzero elements of Fq.In this paper,by using the augmented degree matrix and the result given by Cao,we obtain a formula for the number of rational points of the following equation over Fq:f(x 1,x 2,...,x n)=(a1 x1 x2d+a2 x2 x3d...+a(n-1)x(n-1)xnd+an xn x1d)λ-bx1(d1)x2d2...xn(dn),with ai,b∈Fq*,n≥2,λ〉0 being positive integers,and d,di being nonnegative integers for 1≤i n.This technique can be applied to the polynomials of the form h1λ=h2 with λ being positive integer and h1,h2∈Fq[x 1,x 2,...,x n].It extends the results of the Markoff-Hurwitz-type equations.