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Research draft

equivalence relation

vr.tr.equivalence-relation · XCT.QLT

Let an agent explain equivalence relations and equivalence classes, verify whether a relation is an equivalence, describe examples such as matrix similarity and congruence, and support learning and proof.

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 equivalence relations and equivalence classes, verify whether a relation is an equivalence, describe examples such as matrix similarity and congruence, and support learning and proof.

A binary relation on a set that is reflexive, symmetric and transitive, partitioning the set into equivalence classes of mutually related elements, with examples such as equality, congruence modulo n, similarity and congruence of matrices, and having the same value under a function; equivalence relations are fundamental in mathematics for defining quotient structures and classification, and appear in computer science, logic and linguistics.

What it is for: Relations that partition a set.

It can be explain the definition; verify relations; describe examples; support proofs.

Distinguishing features

Three properties

Equivalence classes

Quotient sets

Ubiquitous

What it looks like

Not physical; a mathematical relation.

How it is recognised

Reflexive, symmetric, transitive

Partitions into classes

A partial order is antisymmetric rather than symmetric

Related models

is a kind of - category

symmetric relation

is a kind of - category

preorder

is related to - contrasting relation

difference

is related to - another logical relation

contradictory

In practice

Families and kinds

equality and identity

congruence modulo n

matrix similarity and congruence

equivalence induced by functions

equivalences in logic and computing

Standards and regulation

Mathematical definitions and notation conventions

Failure modes and hazards

Forgetting to check one property

Confusing equivalence with equality

Ill-defined operations on classes

Also called

matrix similarityorhtogonal matrix similaritymatrix congruencecongruence through orthogonal matriceszero functionconstant functionlinear boolean functionlinear functionGreen's relationsalgebraic spaceK-equivalenceS-equivalenceassociated elementscongruence relation

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 The definition.

Mathematics.

Definition

Properties and classes.

Definition

Definition.

  1. What are reflexivity, symmetry and transitivity, and how do they yield equivalence classes and a partition? definition
  2. How does an equivalence differ from a partial order or a preorder? definition

Examples

Examples.

Examples

Examples.

  1. What are common examples such as congruence modulo n, matrix similarity, matrix congruence and equivalence induced by a function? definition
  2. Which entry fits a specific example? action
Verify Checking and constructing.

Practice.

Check

Verifying a relation.

Check

Verification.

  1. Is this relation an equivalence relation, and what are its classes? action
  2. Which property fails if not? action

Quotient

Quotient constructions.

Quotient

Quotients.

  1. How are quotient sets and structures built, and when are operations on classes well defined? definition
  2. Which entry fits quotient groups? action
Apply Applications.

Context.

Computing

Computing and logic.

Computing

Computing.

  1. How are equivalence relations used in computing, such as union-find, program equivalence and type systems? provenance
  2. Which entry fits a specific algorithm? action

Fields

Other fields.

Fields

Fields.

  1. How do linguistics, statistics and other fields use equivalence classes? provenance
  2. Which references are standard? provenance
Learn Teaching and history.

Education.

Teach

Teaching.

Teach

Teaching.

  1. How can equivalence relations be taught with exercises on partitions and proofs? action
  2. Which misconceptions arise? provenance

History

History.

History

History.

  1. How did the concept of equivalence relation develop in mathematics? provenance
  2. Which entry fits history of set theory? action

What the second pass must settle

  • Should equivalence class be a separate entry?
  • How should textbooks be linked?
  • How should examples be catalogued?