{
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  "kind": "concept",
  "slug": "loop-invariant",
  "name": "Loop invariant",
  "aliases": [
    "invariant"
  ],
  "area": "foundations/correctness-and-invariants",
  "level": "intro",
  "summary": "A statement about the variables of a loop that is true before each step. It is the main tool to prove that a loop is correct.",
  "sources": [
    {
      "book": "isbn:9780262046305",
      "title": "Cormen, Leiserson, Rivest and Stein, Introduction to Algorithms, fourth edition",
      "locator": "Section 2.1"
    },
    {
      "paper": "doi:10.1145/363235.363259",
      "title": "C. A. R. Hoare, An axiomatic basis for computer programming (1969)"
    }
  ],
  "url": "https://algorithm.tamnd.com/loop-invariant/",
  "path": "nodes/foundations/correctness-and-invariants/loop-invariant",
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    "slug": "loop-invariant",
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}