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Research draft

geometric transformation

vr.tr.geometric-transformation · XCT.QLT

Let an agent explain geometric transformations and their classification, relay the hierarchy of transformation groups and matrix representations from mathematical references, describe applications, and distinguish active from passive transformations.

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 geometric transformations and their classification, relay the hierarchy of transformation groups and matrix representations from mathematical references, describe applications, and distinguish active from passive transformations.

A function that maps points of a geometric space to points of the same or another space, such as translations, rotations, reflections, scalings, shears and their compositions, classified by what they preserve, from isometries or congruence transformations that preserve distances, through similarities and affine maps that preserve parallelism, to projective and conformal maps, and viewed either as active transformations that move objects or passive transformations that change the coordinate system, as in a change of basis; geometric transformations underlie geometry, computer graphics, physics and the study of invariants.

What it is for: Not applicable; a mathematical concept.

It can be explain kinds and hierarchy; relay matrix representations; describe applications; distinguish active and passive.

Distinguishing features

Point mappings

Invariant hierarchy

Group structure

Matrix representation

What it looks like

Not a visible object; figures moved, resized or distorted.

Physical character

Erlangen programme: 1872 year - Felix Klein

How it is recognised

Mapping of geometric points

Translations, rotations, reflections, scalings, shears; isometries, similarities, affine, projective maps

A change of basis is the passive view; functions in general need not be geometric

Related models

is a kind of - in registry terms

transformation

is a kind of - in registry terms

active and passive transformation

is classified by - through invariants

Erlangen program

is represented by - in linear and homogeneous coordinates

matrix

In practice

Families and kinds

isometries or congruence transformations: translations, rotations, reflections, glide reflections

similarities including scalings

affine transformations including shear mappings

projective transformations

conformal and Mobius transformations

active and passive transformations and change of basis

invariants such as Riemann invariants in related contexts

Standards and regulation

No regulation; standard mathematical definitions

Failure modes and hazards

Confusing active and passive transformations

Mixing transformation classes

Order of composition errors

Also called

shear mappingcongruence transformationRiemann invariantchange of basis

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 geometric transformation is.

Mathematics.

Definition

Definition and kinds.

Definition

Definition.

  1. What is a geometric transformation, and what are translations, rotations, reflections, scalings and shears? definition
  2. Is the question about a geometric transformation, a change of basis or a general function? boundary

Hierarchy

Hierarchy.

Hierarchy

Hierarchy.

  1. How do isometries, similarities, affine and projective transformations form a hierarchy by invariants? definition
  2. Which entry fits the specific class? action
Compute Representation.

Mathematics.

Matrices

Matrices.

Matrices

Matrices.

  1. How are transformations represented by matrices and homogeneous coordinates, and how are they composed? action
  2. Which references are standard? provenance

Views

Active and passive.

Views

Views.

  1. How do active transformations differ from passive changes of basis, and why does it matter? provenance
  2. Which entry fits change of basis? action
Apply Applications.

Application.

Graphics

Graphics and vision.

Graphics

Graphics.

  1. How are transformations used in computer graphics, robotics and image processing? provenance
  2. Which sources are cited? provenance

Physics

Physics.

Physics

Physics.

  1. How do transformations and invariants such as Riemann invariants appear in physics? provenance
  2. Which entry fits symmetry in physics? action
Context History and teaching.

Context.

History

History.

History

History.

  1. How did Klein Erlangen programme unify geometry through transformation groups? provenance
  2. Which entry fits the history of geometry? action

Teaching

Teaching.

Teaching

Teaching.

  1. How are transformations taught, and what misconceptions arise? provenance
  2. Which entry fits mathematics education? action

What the second pass must settle

  • Should isometry and affine transformation be separate primary entries?
  • How should mathematical references be linked?
  • The registry entry has merged aliases including Riemann invariant; should it be split off?