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Gaurab Tripathi

Publications and source records attributed to Gaurab Tripathi.

7 recordsLinked to original sources

Numerical Semigroups with unique Apery expansions II

In this paper, we carry out a fairly comprehensive study of special classes of numerical semigroups, and their tangent cones, generated by the sequence of partial sums of an arithmetic progression, in embedding dimension $5$. These classes have unique expansions of the Apery set elements.

math.AC

Ideals of the form $I_{1}(XY)$

In this paper we compute Gröbner bases for determinantal ideals of the form $I_{1}(XY)$, where $X$ and $Y$ are both matrices whose entries are indeterminates over a field $K$. We use the Gröbner basis structure to determine Betti numbers for such ideals.

math.AC

Quadrics defined by skew-symmetric matrices

In this paper we propose a model for computing a minimal free resolution for ideals of the form $I_{1}(X_{n}Y_{n})$, where $X_{n}$ is an $n\times n$ skew-symmetric matrix with indeterminate entries $x_{ij}$ and $Y_{n}$ is a generic column matrix with indeterminate entries $y_{j}$. We verify that the model works for $n=3$ and $n=4$ and pose some statements as conjectures. Answering the conjectures in affirmative would enable us to compute a minimal free resolution for general $n$.

math.AC

Transversal Intersection and Sum of Polynomial Ideals

In this paper we derive some conditions for transversal intersection of polynomial ideals. We exhibit some examples. Finally, as an application of the results proved, we compute the Betti numbers for ideals of the form $I_{1}(XY) + J$, where $X$ and $Y$ are matrices and $J$ is the ideal generated by the $2\times 2$ minors of the matrix consisting of any two rows of $X$.

math.AC

Minimal Graded Free Resolution for Monomial Curves in $\mathbb{A}^{4}$ defined by almost arithmetic sequences

Let $\mm=(m_0,m_1,m_2,n)$ be an almost arithmetic sequence, i.e., a sequence of positive integers with ${\rm gcd}(m_0,m_1,m_2,n) = 1$, such that $m_0<m_1<m_2$ form an arithmetic progression, $n$ is arbitrary and they minimally generate the numerical semigroup $Γ= m_0\N + m_1\N + m_2\N + n\N$. Let $k$ be a field. The homogeneous coordinate ring $k[Γ]$ of the affine monomial curve parametrically defined by $X_0=t^{m_0},X_{1}=t^{m_1},X_2=t^{m_3},Y=t^{n}$ is a graded $R$-module, where $R$ is the polynomial ring $k[X_0,X_1,X_3, Y]$ with the grading $°{X_i}:=m_i, °{Y}:=n$. In this paper, we construct a minimal graded free resolution for $k[Γ]$.

math.AC