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Aggregation

Defines Aggregation, aggregated-by, aggregate
Requires
  • morphism

Aggregation is collecting many individual things into one summary. A ledger aggregates accounts — it gathers all the individual account records into a single organized whole. A sum aggregates numbers. A census aggregates individuals into a population count.

Aggregation loses detail in exchange for overview. The individual items still exist, but the aggregate shows only their combined shape. A good aggregation preserves the structure that matters and discards the structure that does not. A bad aggregation hides important differences behind a single number.

When this library uses aggregated-by as a predicate, the subject is the individual items and the object is what collects them together.

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Cite

@misc{emsenn2026-aggregation,
  author    = {emsenn},
  title     = {Aggregation},
  year      = {2026},
  url       = {https://emsenn.net/library/math/terms/aggregation/},
  publisher = {emsenn.net},
  license   = {CC BY-SA 4.0}
}