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inductive definition def or abbrev high

CellState

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CellState enumerates the six values a cell may hold in the one-dimensional Boolean cellular automaton built to evaluate SAT instances via local rules. Researchers constructing parallel SAT solvers inside the Recognition Science model cite it as the discrete alphabet for the tape. The declaration is a plain inductive definition that introduces constructors for Boolean literals, propagating signals, gate markers, wires, and vacancies.

claimLet $S = {0, 1, S, G, W, B}$ be the set of cell states, where $0$ and $1$ are Boolean values, $S$ denotes a propagating signal, $G$ a logic-gate marker, $W$ a passive wire, and $B$ an empty cell.

background

The module constructs cellular-automaton gadgets that realize SAT evaluation with local update rules derived from Rule 110. A Tape is an infinite map from integers to cell states; a Window extracts a finite segment of length $n$; a Neighborhood is the ordered triple of states at positions $i-1$, $i$, $i+1$. Upstream CircuitLedger.Gate supplies the gate-type and parent-index structure that the CA gadgets embed as markers.

proof idea

The declaration is an inductive definition that enumerates six constructors with no computational content or proof obligations.

why it matters in Recognition Science

CellState supplies the state alphabet required by localRule, Neighborhood, Tape and Window, which together establish that SAT instances can be processed by a local, deterministic, reversible CA. This step supports the module claim of $O(n^{1/3} log n)$ evaluation time while preserving ledger compatibility. It interfaces the circuit representation (from CircuitLedger) with the spatial evolution model used for the P-vs-NP argument in Recognition Science.

scope and limits

formal statement (Lean)

  37inductive CellState
  38  | Zero    -- Boolean 0
  39  | One     -- Boolean 1
  40  | Signal  -- Propagating signal
  41  | Gate    -- AND/OR/NOT gate marker
  42  | Wire    -- Passive wire
  43  | Blank   -- Empty cell
  44  deriving DecidableEq, Repr
  45
  46/-- The CA tape is an infinite sequence of cells, but we work with finite windows -/

used by (4)

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depends on (10)

Lean names referenced from this declaration's body.