{
  "id": "model-theory",
  "domain": "foundations-logic",
  "type": "Concept",
  "title": "Model Theory",
  "slug": "model-theory",
  "url": "/mathematics/foundations-logic/model-theory/",
  "summary": "Studies the relationship between formal languages and the structures (models) that satisfy them. Löwenheim-Skolem, compactness, Morley categoricity theorem, Shelah's stability theory, o-minimality, applications to algebra.",
  "added_to_codex": "2026-07-09",
  "last_verified": "2026-07-09",
  "sources": [
    {
      "tier": 1,
      "citation": "Marker, D. (2002). Model Theory: An Introduction. Springer."
    },
    {
      "tier": 1,
      "citation": "Shelah, S. (1990). Classification Theory. Revised ed."
    },
    {
      "tier": 2,
      "citation": "Hodges, W. (1993). Model Theory. Cambridge University Press."
    },
    {
      "tier": 3,
      "citation": "Chang, C.C. and Keisler, H.J. (1990). Model Theory. 3rd ed."
    }
  ],
  "entry_status": "live",
  "reading_levels_available": [
    "curious",
    "exploring",
    "deep_dive"
  ],
  "completeness": 1.0,
  "codex_version": "2.5"
}