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Research draft

edge

vr.tr.edge · XCT.QLT

Let an agent define edges in geometry and their counting relations, relate them to edges in graph theory, help compute edge counts and lengths, and separate the concept from unrelated aliases.

Thing Registry Cross-cutting context

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify

Researched by: Claude

Purpose and description

Let an agent define edges in geometry and their counting relations, relate them to edges in graph theory, help compute edge counts and lengths, and separate the concept from unrelated aliases.

In geometry, a line segment joining two vertices of a polygon, polyhedron or higher polytope and forming part of its boundary, as the sides of a triangle or the twelve edges of a cube; edges are counted in relations such as the Euler formula, are generalised in graph theory to connections between nodes, and the registry entry also gathers aliases for elementary particle names and a baseline, which are unrelated.

What it is for: Describing the boundaries of polygons and polytopes.

It can be define edges and their properties; relate to graph theory edges; compute edge counts and lengths; separate unrelated aliases.

Distinguishing features

One-dimensional boundary element

Joins two vertices

Counted by Euler relations

Generalised in graphs

What it looks like

A straight segment where two faces of a solid meet or between two vertices of a polygon.

Physical character

edges of a cube: 12 count

Euler formula for convex polyhedra: V - E + F = 2 relation

How it is recognised

Segment between vertices on a boundary

Sides of polygons, edges of polyhedra

Faces are two-dimensional; vertices are points; graph edges may not be geometric

Related models

is a kind of - in registry terms

line segment

is part of - in registry terms

polytope

joins - two of them

vertex

is generalised by - connections between nodes

edge in graph theory

In practice

Families and kinds

sides of polygons

edges of polyhedra

edges of higher polytopes

edges in graph theory

edges in meshes and computer graphics

Standards and regulation

ISO 80000-2 notation for geometry

Failure modes and hazards

Confusing edges with faces or vertices

Sense confusion with unrelated aliases

Miscounting edges in complex polytopes

Also called

TrionTetronpentonhexonbase line

Where this came from

wikidata · CC0 1.0

Also registered as vr.tr.edge-artifact

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.

Define What an edge is.

Definition.

Definition

Definition.

Definition

Definition.

  1. What is an edge in geometry, and how does it relate to vertices and faces? definition
  2. Is the question about geometric edges, graph edges or an unrelated sense? boundary

Graphs

Edges in graphs.

Graphs

Graphs.

  1. How does the graph theory notion of edge generalise the geometric one? definition
  2. Which entry fits graph theory? action
Compute Counting and measuring.

Computation.

Counting

Counting edges.

Counting

Counting.

  1. How are edges counted using the Euler formula and combinatorial reasoning? action
  2. What is the count for the polytope in question? measurement

Lengths

Edge lengths.

Lengths

Lengths.

  1. How are edge lengths and angles computed for regular and general solids? action
  2. Which entry fits polyhedron? action
Apply Applications.

Application.

Graphics

Meshes and graphics.

Graphics

Graphics.

  1. How are edges represented in meshes and computer graphics? provenance
  2. Which entry fits polygon mesh? action

Structures

Structures.

Structures

Structures.

  1. How do edges figure in crystallography and structural frameworks? provenance
  2. Which references are standard? provenance
Context History and teaching.

Context.

History

History.

History

History.

  1. How did Euler and later mathematicians develop edge counting relations? provenance
  2. Which entry fits the history of topology? action

Teach

Teaching.

Teach

Teaching.

  1. How are edges, faces and vertices taught, and which are confused? provenance
  2. Which sources are cited? provenance

What the second pass must settle

  • Should graph edge be a separate entry?
  • How should geometry references be linked?
  • The registry entry has merged aliases for particle names and a baseline; should they be removed?