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Research draft

binary relation

vr.tr.binary-relation · XCT.QLT

Let an agent explain binary relations and their formal definition and properties, describe important kinds and their uses, support proofs and exercises, and support learning in mathematics and computing.

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 explain binary relations and their formal definition and properties, describe important kinds and their uses, support proofs and exercises, and support learning in mathematics and computing.

In mathematics, a relation between the elements of two sets, formally a set of ordered pairs, which may hold or not for each pair, including relations on a single set with properties such as reflexivity, symmetry, transitivity and antisymmetry, and special kinds such as equivalence relations, partial and total orders, functions and graphs; binary relations are fundamental in set theory, logic, algebra, databases and computer science.

What it is for: Sets of ordered pairs between elements.

It can be explain definition and properties; describe kinds; support proofs; support learning.

Distinguishing features

Ordered pairs

Properties

Composition and inverse

Representable as graphs or matrices

What it looks like

Not physical; a mathematical object.

How it is recognised

Set of ordered pairs

Reflexive, symmetric, transitive and other properties

A function is a special relation; an n-ary relation has more places

Related models

is a kind of - category

relation

is related to - relations between points

point relation

is related to - relations between units

unit relation

is related to - order relations on real numbers

irrational

In practice

Families and kinds

equivalence relations

partial and total orders

functions as relations

relations in databases

relations as directed graphs

Standards and regulation

Mathematical notation conventions

Curriculum standards for discrete mathematics

No regulation of the concept

Failure modes and hazards

Confusing relation properties

Confusing relations with functions

Notation ambiguity

Where this came from

wikidata · CC0 1.0

Drafted structure

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

Understand What a binary relation is.

Mathematics.

Concept

Definition.

Concept

Concept.

  1. What is a binary relation formally, and how are domain, codomain, composition and inverse defined? definition
  2. Which entry fits set theory? action

Properties

Properties.

Properties

Properties.

  1. What are reflexivity, symmetry, antisymmetry, transitivity and totality, and how are they checked? definition
  2. Which property is meant? boundary
Kinds Important kinds.

Mathematics.

Equivalence

Equivalence and order.

Equivalence

Equivalence.

  1. How do equivalence relations, partial orders and total orders arise, and what are their uses? definition
  2. Which entry fits order theory? action

Functions

Functions and graphs.

Functions

Functions.

  1. How are functions and directed graphs special cases or representations of relations? definition
  2. Which entry fits graph theory? action
Apply Applications and proofs.

Practice.

Prove

Proving properties.

Prove

Proof.

  1. How can it be proved that this relation has or lacks a given property? action
  2. Which entry fits proof techniques? action

Computing

Computing.

Computing

Computing.

  1. How are relations used in databases, logic programming and formal methods? provenance
  2. Which entry fits relational databases? action
Learn History and teaching.

Education.

History

History.

History

History.

  1. How did the theory of relations develop from De Morgan and Peirce to modern set theory? provenance
  2. Which references are standard? provenance

Teach

Teaching.

Teach

Teaching.

  1. How can relations be taught in discrete mathematics? action
  2. Which misconceptions arise? provenance

What the second pass must settle

  • Should equivalence relations be a separate entry?
  • How should textbooks be linked?
  • How should exercises be linked?