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    "name": "Propositional Logic",
    "subject": "logic",
    "variant": "classical",
    "description": "Hilbert-style axiomatic development of classical propositional logic. Three axioms (Łukasiewicz P2), modus ponens, definitions of disjunction, conjunction, biconditional, and key theorems (double negation, De Morgan, excluded middle, deduction theorem).",
    "structure": {
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  "metadata": {
    "created": "2026-03-15",
    "lastUpdated": "2026-03-15",
    "version": "1.0.0",
    "license": "CC BY 4.0",
    "authors": [
      "Welz, G."
    ],
    "methodology": "Programming Framework",
    "citation": "Welz, G. (2026). Propositional Logic Dependency Graph. Programming Framework.",
    "keywords": [
      "propositional logic",
      "Hilbert",
      "Łukasiewicz",
      "tautology",
      "modus ponens"
    ]
  },
  "sources": [
    {
      "id": "frege",
      "type": "primary",
      "authors": "Frege, G.",
      "title": "Begriffsschrift",
      "year": "1879",
      "notes": "First axiomatic propositional logic"
    },
    {
      "id": "lukasiewicz",
      "type": "primary",
      "authors": "Łukasiewicz, J.",
      "title": "Elements of Mathematical Logic",
      "year": "1929",
      "notes": "P2: 3 axioms"
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      "id": "wikipedia",
      "type": "digital",
      "title": "Propositional calculus",
      "url": "https://en.wikipedia.org/wiki/Propositional_calculus",
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