Foundations: Einstein (Special & General Relativity, spacetime geometry, equivalence) + bidirectional strengthening of Time / Relativity / Curvature / Mass

[jonassiebler]

Summary

First theme-branch of the next physics-anchor wave: Spacetime geometry, Relativity, Curvature, Worldline, Equivalence principle.

What lands

• New Foundations page: /foundations/einstein-relativity-spacetime-geometry
  • Special Relativity (1905): invariance of c, relativity of simultaneity, mass-energy equivalence
  • General Relativity (1915/1916): equivalence principle, spacetime curvature, geodesics, Worldline as primary object
  • Reading protocol respected (Einstein first → Inspiration → IE additions)
  • Primary sources linked (Wikisource + Archive.org)
• Foundations index updated (chronological placement)
• Bidirectional strengthening of four Core Concept pages:
  • /framework/time – Worldline priority now explicitly anchored to Einstein
  • /framework/relativity – frame-dependent observation rooted in physical relativity
  • /framework/curvature – geometric warping of the manifold (not force-in-flat-space)
  • /framework/mass – dual role (inertia + source of geometry) via equivalence + E=mc²

Explicit non-claims

• Isomorphy work only. No claim that identity obeys the Einstein field equations.
• Multi-force layer (Strong Binding + Electromagnetism) remains parallel, not replaced.
• No em-dashes; inline tags kept on one line with surrounding spaces.

Relation to other open work

• Complements the force/binding Foundations (Faraday–Maxwell–Boltzmann–Yukawa–Gell-Mann) and the Newton/Leibniz pair.
• Highest-leverage single Foundations addition for the geometric core of the framework.

No merge until explicit approval.

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