arXiv subjects

Steven R. Lippold

Publications and source records attributed to Steven R. Lippold.

5 recordsLinked to original sources

arXiv2024

Twin-star hypothesis and cycle-free $d$-partitions of $K_{2d}$ ]{Twin-star hypothesis and cycle-free $d$-partitions of $K_{2d}$

In this paper we study an equivalence relation defined on the set of cycle-free $d$-partitions of the complete graph $K_{2d}$. We discuss a conjecture which states that this equivalence relation has only one equivalence class, and show that the conjecture is equivalent with the so called twin-star hypothesis. We check the conjecture in the case $d=4$ and disuses how this relates to the determinant-like map $det^{S^2}$.

math.CO↗

arXiv2023

The Algebra of $S^2$-Upper Triangular Matrices

Based on work presented in [4], we define $S^2$-Upper Triangular Matrices and $S^2$-Lower Triangular Matrices, two special types of $d\times d(2d-1)$ matrices generalizing Upper and Lower Triangular Matrices, respectively. Then, we show that the property that the determinant of an Upper Triangular Matrix is the product of its diagonal entries is generalized under our construction. Further, we construct the algebra of $S^2$-Upper Triangular Matrices and give conditions for an LU-Decomposition with $S^2$-Lower Triangular and $S^2$-Upper Triangular Matrices, respectively.

math.RA↗

arXiv2023

Existence of the Map $det^{S^3}$

In this paper we show the existence of a nontrivial linear map $det^{S^3}:V_d^{\otimes\binom{3d}{3}}\to k$ with the property that $det^{S^3}(\otimes_{1\leq i<j<k\leq 3d}(v_{i,j,k}))=0$ if there exists $1\leq x<y<z<t\leq 3d$ such that $v_{x,y,z}=v_{x,y,t}=v_{x,z,t}=v_{y,z,t}$. This gives a partial answer to a conjecture from [10]. As an application, we use the map $det^{S^3}$ to study those d-partitions of the complete hypergraph $K^3_{3d}$ that have zero Betti numbers. We also discuss algebraic and combinatorial properties of a map $det^{S^r}:V_d^{\otimes\binom{rd}{r}}\to k$ which generalizes the determinant map, the map $det^{S^2}$ from [9], and $det^{S^3}$.

math.RA↗

arXiv2021

Partitions of the complete hypergraph $K_6^3$ and a determinant like function

In this paper we introduce a determinant-like map $det^{S^3}$ and study some of its properties. For this we define a graded vector space $Λ^{S^3}_V$ that has similar properties with the exterior algebra $Λ_V$ and the exterior GSC-operad $Λ^{S^2}_V$ from \cite{sta2}. When $dim(V_2)=2$ we show that $dim_k(Λ^{S^3}_{V_2}[6])=1$ which gives the existence and uniqueness of $det^{S^3}$. We also give an explicit formula for $det^{S^3}$ as a sum over certain $2$-partitions of the complete hypergraph $K_6^3$.

math.CO↗

arXiv2021

Edge partitions of the complete graph and a determinant like function

In this paper we prove the case $dim(V_3)=3$ of a conjecture about the exterior operad $Λ^{S^2}_{V_d}$. For this we introduce a collection of natural involutions on the set of homogeneous cycle-free $d$-partitions of the complete graph $K_{2d}$, and show that these involutions correspond to the relations in $Λ^{S^2}_{V_d}(2d+1)$. When $d=3$ this correspondence allows us to give an explicit description of a determinant-like map and to settle the above mentioned conjecture.

math.CO↗