## Interpretation of Momentum?

Interpretation of Momentum?

Index position by a grid of light cones , which is effectively the causal graph [ “grid of elementary light cones” ]

Any effect propagates through spacetime on the edges of these light cones.... (everything is at least locally going on a null geodesic) [cf refractive index of water, etc.]

Possible claim: more energy, more nodes

Effective dimension of spacetime cones....

## What Spacelike Hypersurfaces Correspond to an Inertial Frame?

What Spacelike Hypersurfaces Correspond to an Inertial Frame?

The surface must always be spacelike... can we enumerate all spacelike surfaces through a point?

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Given an event, find the spacelike separated events

Can we find a sequence of surfaces that fill the spacetime, but are always spacelike?

The foliations correspond to layerings of the causal graph

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LayeredGraphPlot

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Claim is that a hypersurface is a collection of edges (i.e. a bunch of pieces of elementary light cones)

Foliation is a parametrized enumeration of edges

Layering defines the observer’s frame

Does following the elementary light cones propagate you smoothly from one hypersurface to the next?

Jonathan’s claim: density of edges defines momentum; complete graph is maximum density