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math.CO2026

Linear Tur'an Numbers of Four-Edge Uniform Paths via Incidence Rank

Mahesh Ramani

Let denote the -uniform expansion of the graph path with four edges. We prove that every -vertex linear -uniform -free hypergraph has at most edg…

math.CO2026

Incidence Rank and Bounded Defect for Linear Hypergraphs with Cograph Line Graphs

Mahesh Ramani

Let be the edge--vertex incidence matrix of a finite linear -uniform hypergraph whose line graph is a cograph, and define \[ R_s(H)=(s+1)\operatorname{rank}_{\mathbb R}N(…

math.CO2026

Blocking Amalgamations, Maximal Arcs, and Generalized Crowns

Mahesh Ramani

Let be the -uniform -crown and put . For a finite linear intersecting -uniform hypergraph , let be the minimum size of a set meeting every…

math.CO2026

Robust Repulsion for Growing Crowns in Linear Hypergraphs

Mahesh Ramani

Put , , and . For an edge of a linear -free -uniform hypergraph, define \[ δ_H(e)=\sum_{v\in e}\frac{1}{d_H(v)}-\frac{r}{D}. \] The defect s…

math.CO2026

A Matrix-Degree Obstruction to Rational Generation of Boolean-Lattice Pseudo-Roots

Mahesh Ramani

For the neighborhood seed associated with the four-vertex path , the diamond operations do not recover all Boolean-lattice pseudo-roots. The corresponding question for unrestr…

math.CO2026

Cographs and Minimum Diamond-Generating Edge Sets in Boolean Lattices

Mahesh Ramani

We study a local closure operation on the cover edges of a Boolean lattice: whenever the two lower edges or the two upper edges of a square face are present, all four edges of that…

math.CO2026

Spectral Theory of the Toroidal 3D Queen Graph

Mahesh Ramani

We study the adjacency spectrum of the toroidal three-dimensional queen graph on . Since is a Cayley graph on an abelian group, its adjacency matrix i…

math.CO2026

On the Structure of 3D Queen Domination

Mahesh Ramani

We study the domination number of the three-dimensional queen graph. The main result is a stratified theorem computing, for each position type -- c…