Results 161 to 170 of about 349,803 (277)

On Tight Tree‐Complete Hypergraph Ramsey Numbers

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT Chvátal showed that for any tree T $T$ with k $k$ edges, the Ramsey number R ( T , n ) = k ( n − 1 ) + 1 $R(T,n)=k(n-1)+1$. For r = 3 $r=3$ or 4, we show that, if T $T$ is an r $r$‐uniform nontrivial tight tree, then the hypergraph Ramsey number R ( T , n ) = Θ ( n r − 1 ) $R(T,n)={\rm{\Theta }}({n}^{r-1})$.
Jiaxi Nie
wiley   +1 more source

A Coarse Geometric Approach to Graph Layout Problems

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT We define a range of new coarse geometric invariants based on various graph–theoretic measures of complexity for finite graphs, including treewidth, pathwidth, cutwidth and bandwidth. We prove that, for bounded degree graphs, these invariants can be used to define functions which satisfy a strong monotonicity property, namely, they are ...
Wanying Huang   +3 more
wiley   +1 more source

Orientations of Graphs With at Most One Directed Path Between Every Pair of Vertices

open access: yesJournal of Graph Theory, EarlyView.
ABSTRACT Given a graph G $G$, we say that an orientation D $D$ of G $G$ is a KT orientation if, for all u , v ∈ V ( D ) $u,v\in V(D)$, there is at most one directed path (in any direction) between u $u$ and v $v$. Graphs that admit such orientations have been used to construct graphs with large chromatic number and small clique number that served as ...
Barbora Dohnalová   +3 more
wiley   +1 more source

The shifted convolution problem in function fields. [PDF]

open access: yesMath Ann
Florea A, Lalín M, Malik A, Sahay A.
europepmc   +1 more source

Impact of 1024‐Matrix Size on Perforating Artery Visualisation in Cerebral Computed Tomography Angiography Using a 64‐Slice CT Scanner

open access: yesJournal of Medical Radiation Sciences, EarlyView.
This study investigated whether using a larger image matrix (1024 × 1024 pixels instead of 512 × 512) improves the visibility of tiny brain arteries on CT scans performed with standard 64‐slice scanners. While physical image quality measurements remained unchanged, the larger matrix provided finer digital sampling of blood vessel structures, resulting ...
Hokuto Nagumo   +5 more
wiley   +1 more source

Isometries of Spacetimes Without Observer Horizons. [PDF]

open access: yesCommun Math Phys
García-Heveling L, Zeghib A.
europepmc   +1 more source

Automated theorem proving

open access: yes, 2016
Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2016, Director: Juan Carlos Martínez ...
openaire   +1 more source

Last‐minute coordination: Adapting to demand to support last‐mile operations

open access: yesJournal of Operations Management, Volume 71, Issue 2, Page 176-194, March 2025.
Abstract In the highly competitive e‐commerce industry, customer‐facing warehouses are crucial as the “order penetration points” for e‐commerce last‐mile operations. This research examines how warehouses use last‐minute coordination, an unstructured mechanism, to ensure sufficient inventory at the order penetration points. Previous research has focused
Kedong Chen   +3 more
wiley   +1 more source

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