Spatial Trace Function σ #
[Gaw09] [Kri98] [Tal00] [Zwa05] [ZW00]
The spatial dimension of event structure: σ maps events to their spatial
trajectories (paths). This parallels τ (the temporal trace, Event.runtime)
and the thematic-role dimension θ as Krifka/Zwarts trace functions — each a
Mereology.IsSumHom into a different domain (intervals, paths, entities).
Three-Dimension Picture #
Temporal: Events →τ Intervals →dur ℚ (temporal dimension)
Spatial: Events →σ Paths →dist ℚ (spatial dimension)
Object: Events →θ Entities →μ ℚ (object dimension)
All three use the same QUA/CUM pullback mechanism via MereoDim.
Key Results #
Bounded path → telic VP (§4): QUA path predicates pull back through σ to yield QUA (telic) VP predicates. "Walk to the store" is telic because "to the store" denotes a QUA set of paths (no proper subpath of a to-the-store path is also to-the-store).
Unbounded path → atelic VP (§4): CUM path predicates pull back through σ to yield CUM (atelic) VP predicates. "Walk towards the store" is atelic because "towards the store" denotes a CUM set of paths.
Trace Class #
Spatial trace: maps events to their spatial trajectories.
[Zwa05], [Gaw09]: σ(e) is the path traversed in event e.
Parallels the temporal trace τ (Event.runtime).
σ is required to be a sum homomorphism: σ(e₁ ⊕ e₂) = σ(e₁) ⊕ σ(e₂).
This ensures CUM pulls back through σ (atelic paths → atelic VPs).
For QUA pullback, injectivity must be assumed separately
(via σ_mereoDim), just as for τ.
Extract the spatial path of an event.
σ preserves sums: σ(e₁ ⊕ e₂) = σ(e₁) ⊕ σ(e₂).
Instances
IsSumHom Instance for σ #
σ as an IsSumHom instance, from Trace.σ_map_sup.
Enables cum_pullback to work automatically for σ.
MereoDim for σ #
σ with injectivity is a MereoDim: the spatial dimension is a mereological morphism, enabling QUA pullback through spatial paths.
Equations
- ⋯ = ⋯
Instances For
Telicity Transfer Through σ #
Bounded path predicate → telic VP. "Walk to the store" is telic because "to the store" is QUA (no proper subpath of a to-the-store path is also to-the-store) and QUA pulls back through σ. [Zwa05]: bounded PPs yield telic VPs.
Unbounded path predicate → atelic VP. "Walk towards the store" is atelic because "towards the store" is CUM and CUM pulls back through the σ sum homomorphism. [Zwa05]: unbounded PPs yield atelic VPs.
PathShape → Telicity Bridge #
Map PathShape to Telicity: bounded/source → telic, unbounded → atelic. [Zwa05]: the boundedness of a directional PP determines whether the VP it creates is telic or atelic.
This is the spatial analog of the QUA/CUM ↔ telic/atelic correspondence
over Features.VendlerClass.telicity (see Features.telic_classes).
Equations
- Semantics.Spatial.Trace.pathShapeToTelicity Semantics.Spatial.Path.PathShape.bounded = Features.Telicity.telic
- Semantics.Spatial.Trace.pathShapeToTelicity Semantics.Spatial.Path.PathShape.source = Features.Telicity.telic
- Semantics.Spatial.Trace.pathShapeToTelicity Semantics.Spatial.Path.PathShape.unbounded = Features.Telicity.atelic
Instances For
Bounded paths are telic.
Source paths are telic.
Unbounded paths are atelic.
PathShape telicity agrees with PathShape boundedness licensing: telic ↔ licensed (closed scale), atelic ↔ blocked (open scale). This connects the spatial classification to the scale-theoretic one.
LicensingPipeline instance for PathShape via the pathShapeToTelicity
bridge. Co-located with the bridge per the convention noted in
Core/Scales/Defs.lean (instances live with their type).
Equations
- One or more equations did not get rendered due to their size.