Reduced Sombor Index Calculator

reduced-degree Euclidean norm

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About Reduced Sombor Index Calculator

A reduced Sombor index calculator computing SOred(G) = Σ √((dᵢ-1)²+(dⱼ-1)²). Réti-Gutman (2021). Uses reduced degrees (d-1). SOred = 0 for K₂ and stars (all reduced degrees include 0). Captures internal connectivity beyond pendant bonds. Client-side.

Reduced Sombor Index Calculator Features

  • SOred(G)
  • √((d-1)²+(d-1)²)
  • Reduced deg.
  • Réti '21
  • Common graphs
Reduced Sombor SOred(G) = Σ √((dᵢ-1)²+(dⱼ-1)²). Uses d-1 (reduced degree) instead of d. Pendant vertices have reduced degree 0, contributing nothing. SOred captures connectivity beyond the trivial pendant bonds.

How to Use

Select graph:

  • SOred: Reduced Sombor
  • d-1: Reduced deg.
  • vs SO: Compare

Reduced Degree

d(v)-1: pendant vertex → 0 (no excess). Hub with d=5 → 4 excess connections. Reduced degree measures connectivity 'beyond the minimum'. Removes trivial single-bond contribution.

Bounds

SOred = 0 for stars (all leaves have reduced degree 0). SOred(K_n) = n(n-1)/2 · (n-2)√2. Trees: SOred depends only on internal vertices.

Step-by-Step Instructions

  1. 1Select graph.
  2. 2Compute d-1 for all vertices.
  3. 3For each edge: √((d₁-1)²+(d₂-1)²).
  4. 4Sum all norms.
  5. 5Compare with SO.

Reduced Sombor Index Calculator — Frequently Asked Questions

Why reduced degree?+

In chemistry: every atom needs at least one bond. d-1 measures 'excess' bonding. Pendant atoms (degree 1) have zero excess — they contribute nothing to SOred. Focus on molecular backbone.

SOred = 0 when?+

SOred = 0 ⟺ every edge has at least one endpoint with degree 1. Stars achieve this: every edge connects hub to leaf (leaf has d-1=0, making norm = |dhub-1|). K₂: both d-1=0.

SOred vs SO relationship?+

SOred ≤ SO always (d-1 ≤ d). The gap SO - SOred measures pendant contribution. For trees: gap is large (many leaves). For dense graphs: gap is small (few or no leaves).

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