Reverse Wiener Index Calculator

diameter-complement distance

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About Reverse Wiener Index Calculator

A reverse Wiener index calculator computing Λ(G) = Σ_{i<j} [diam(G) - d(i,j)]. Hosoya (1988 concept), named by Balaban-Randić (2004). Complements Wiener: large if vertices are close. Λ + W = diam·n(n-1)/2. Client-side.

Reverse Wiener Index Calculator Features

  • Λ(G)
  • diam−d
  • Λ+W=const
  • Complement
  • Common graphs
Reverse Wiener Λ(G) = Σ [diam - d(i,j)]. Flips Wiener: close vertices contribute more. Λ + W = diam·C(n,2). Λ(K_n) = 0 (all distances = diam = 1). High Λ = many close pairs despite large diameter.

How to Use

Select graph:

  • Λ: Reverse Wiener
  • diam−d: Per pair
  • Λ+W: Verify

W Complement

Λ + W = diam·n(n-1)/2. If you know W and diam, you get Λ for free. Λ measures 'closeness excess': how much closer pairs are than the worst case (diameter).

Bounds

Λ(K_n) = 0. Λ(P_n) = maximum among trees. Λ ≥ 0 always. For d-regular: Λ depends on diameter and distance distribution.

Step-by-Step Instructions

  1. 1Select graph.
  2. 2Find diameter.
  3. 3For each pair: diam - d(i,j).
  4. 4Sum all terms.
  5. 5Verify Λ+W.

Reverse Wiener Index Calculator — Frequently Asked Questions

Why reverse?+

W penalizes distance. Λ rewards closeness: (diam-d) is large when d is small. Same information, opposite perspective. Sometimes Λ correlates better with chemical properties.

Λ + W = constant?+

Yes! Λ + W = diam·n(n-1)/2. This is elegant: the two indices sum to a value depending only on n and diameter. They partition the 'total distance potential'.

When is Λ = 0?+

Λ = 0 ⟺ diam = 1 ⟺ complete graph. All distances equal diameter, so diam-d = 0 for every pair. Only K_n achieves this.

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