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Allen Interval Visualizer

Drag the interval endpoints to explore all 13 of Allen's temporal relations. The relation between intervals A and B is computed in real-time by the fabula WASM engine.

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The 13 Relations

RelationDescriptionInverse
BeforeA ends before B startsAfter
MeetsA ends exactly where B startsMetBy
OverlapsA starts first, they share time, B ends lastOverlappedBy
StartsA and B start together, A ends firstStartedBy
DuringA is entirely within BContains
FinishesA and B end together, A starts laterFinishedBy
EqualsA and B have identical start and endEquals

Each relation has a unique inverse. Together they form a complete, mutually exclusive classification of how two bounded intervals can relate in time.

  • Temporal Model -- how fabula uses Allen algebra for stage ordering and explicit constraints.
  • Interval Reference -- full API for Interval<T> and AllenRelation.