Graph Sphericity Calculator

sphere intersection dimension

CalculatorsFreeNo Signup
4.6(595 reviews)
All Tools

Loading tool...

About Graph Sphericity Calculator

A graph sphericity calculator computing sph(G): minimum d for G = intersection graph of spheres (balls) in ℝ^d with Euclidean metric. Uses L₂ metric. sph ≤ n-1. Unit disk: sph=2 with equal radii. Related to dot product dimension. Client-side.

Graph Sphericity Calculator Features

  • sph(G)
  • L₂ metric
  • Unit disk=2
  • vs box
  • Common graphs
Sphericity sph(G): minimum d for G = intersection of d-balls (Euclidean). Different from boxicity (L∞ metric). Unit disk graphs: sph ≤ 2. Every graph: sph ≤ n-1. Captures Euclidean intersection structure.

How to Use

Select graph:

  • sph: Sphericity
  • vs box: Compare L₂ vs L∞
  • Metric: Euclidean

L₂ vs L∞

Boxicity uses L∞ (max coordinate). Sphericity uses L₂ (Euclidean). Different norms give different intersection graphs! Neither dominates: some graphs have box < sph, others sph < box.

Applications

Sensor networks: spherical coverage regions. Molecular modeling: atom van der Waals radii. Geography: circular service areas. Any domain with Euclidean proximity relationships.

Step-by-Step Instructions

  1. 1Select graph.
  2. 2Compute sphericity.
  3. 3Compare with boxicity.
  4. 4Euclidean embedding.
  5. 5Apply bounds.

Graph Sphericity Calculator — Frequently Asked Questions

How is sphericity different from boxicity?+

Boxicity: axis-aligned boxes (L∞). Sphericity: balls (L₂). Different geometric shapes. Neither is always smaller. Depends on graph structure which metric gives lower dimension.

What about unit disk graphs?+

Unit disk graphs in 2D: equal-radius circles. Special case of sphericity with d=2 and equal radii. Important in wireless networking. Recognition is NP-hard even for unit disks!

Is sphericity computable?+

NP-hard in general (like boxicity). For special classes: interval (sph=1), unit disk (sph≤2) are recognizable with difficulty. Active research on approximation algorithms.

Share this tool: