Collection of Scientific and Other Classifications

[niplav]

One might think all we do is stamp-collecting.

• Mathematics

  • Classification of simple finite groups

  • Classification of manifolds and surfaces

    • Regular polytopes

    • Elementary cellular automata

    • Symmetry groups

      • Wallpaper groups

      • Space groups

      • Bieberbach groups

    • Classification of reversible bit operations

      • Also Post’s lattice

    • Complexity classes and their relations

      • Arithmetic hierarchy

      • Polynomial hierarchy

      • Chomsky hierarchy

    • Stability theory

      • Poincaré maps of linear autonomous systems

    • Game theory

      • Classification of $2\times 2$ normal-form games

• Physics

  • Standard Model

    • Classifies all fundamental particles

  • Cosmology

    • Stellar classification

    • Galaxy classification

    • Orbital mechanics

      • Lagrange points

      • Different types of orbits

• Chemistry

  • Periodic Table of Elements

  • Synthetic polymers

  • Hazardous materials classification

• Biology

  • Phylogenetic tree of life

  • Linnean taxonomy

  • Classification of viruses, e.g. the ICTV classification

  • Various schemes for biomes, e.g. the Holdridge life zones

• Earth science

  • Geologic time scale

  • Cloud genera

  • Soil classification: USDA soil taxonomy

  • Classifications of snow and snowflakes

  • Classification of minerals, separated beautifully into:

    • Organic

    • Silicate

    • Non-silicate

  • Also meteorites

  • Trewartha and Köppen climate classifications

• Linguistics

  • International phonetic alphabet

  • Language families, list

  • Unicode

• Medicine

  • Medical classification: ICD-10

    • Leading to many many subclassifications, e.g. of asthma, breast cancer, obesity, of course diabetes (type 1 and type 2) and strokes (ischemic and hemorrhagic)…

  • Psychiatric classification: DSM-5

  • Blood types

• Psychology

  • Various proposed classifications of emotions

• Culture

  • Music

    • Musical genres

    • Musical instruments, especially percussion instruments

  • Food

    • Wines

    • Champagne

• Meditation

  • Jhanas

  • Maps of insight

• Dewey Decimal classification

A classification of classifications, if you will.

Sporadic elements include classifications of cars, demons, fairies, and swords.