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def definition def or abbrev high

strictBooleanRealization

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The definition assembles the strict Boolean realization of the logic laws with carrier Bool and comparison cost that returns zero on equality and one on distinction. Researchers tracing discrete models in the forcing chain cite it to obtain the free iteration object LogicNat from propositional generators. The construction is a direct structure instantiation that wires in the Boolean cost lemmas and sets the excluded-middle and composition laws to True.

claimThe strict Boolean realization is the structure whose carrier is the set of Boolean values, whose cost function is the Boolean comparison cost (zero when arguments are equal, one otherwise), whose composition operation is exclusive-or, whose generator is true, and whose identity element is false.

background

StrictLogicRealization is the record type that packages a carrier set, a cost function to Nat, a composition operation, a generator, and the laws of logic (identity, non-contradiction, excluded middle, composition, invariance, nontriviality). The module supplies the strict discrete Boolean model in which the carrier orbit collapses to two points while the forced arithmetic remains the free iteration object. boolCost is the function that returns 0 on equal Booleans and 1 on distinct ones; boolCost_self and boolCost_symm are the lemmas establishing that this cost satisfies the identity and symmetry laws. LogicNat is the inductive type with constructors identity and step that encodes the orbit generated by repeated application of the generator.

proof idea

The definition is a direct structure instantiation. It assigns Bool to the carrier field, Nat to the cost field, boolCost to the compare field, xorBool to the compose field, false to the one field, and true to the generator field. The identity and non-contradiction laws are discharged by the lemmas boolCost_self and boolCost_symm; the remaining laws are supplied as the proposition True; the nontriviality law is proved by a single simp [boolCost] tactic.

why it matters in Recognition Science

This definition supplies the discrete Boolean model required by the NaturalNumberObject module. It is invoked to prove that the free orbit is an NNO (boolean_freeOrbit_isNNO), that the interpretation map collapses (interpret_collapses), and that the interpretation equals the parity map (interpret_eq_parity). The same definition appears in the cross-realization equivalence strictPositiveRatio_arith_equiv_strictBoolean, showing that positive-ratio and Boolean realizations force identical arithmetic. It therefore closes the discrete half of the invariance argument that links the strict forcing chain to LogicNat.

scope and limits

Lean usage

def exampleOrbit := StrictLogicRealization.FreeOrbit strictBooleanRealization

formal statement (Lean)

  36def strictBooleanRealization : StrictLogicRealization where
  37  Carrier := Bool

proof body

Definition body.

  38  Cost := Nat
  39  zeroCost := inferInstance
  40  compare := boolCost
  41  compose := xorBool
  42  one := false
  43  generator := true
  44  identity_law := boolCost_self
  45  non_contradiction_law := boolCost_symm
  46  excluded_middle_law := True
  47  composition_law := True
  48  invariance_law := True
  49  nontrivial_law := by
  50    simp [boolCost]
  51
  52/-- Strict Boolean forced arithmetic is canonically `LogicNat`. -/

used by (5)

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depends on (19)

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