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DFA Reachable State Inventory

Compute finite declared automaton forward reachability from an explicit start state; no minimization or language equivalence claim.

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Description

List automaton states reachable from an explicit start in breadth-first discovery order.

A deterministic transition maps a state and one literal alphabet symbol to at most one next state. A partial table may leave some pairs undefined; a complete table defines every state/symbol pair. Tracing one word, exploring all graph paths and changing the accepting set are distinct operations. IDs and symbols use exact string identity.

List automaton states reachable from an explicit start in breadth-first discovery order.

When to use this tool

Use the reachable inventory to explore all available graph paths from a declared start state.

How to use the tool and how it works

  1. Enter transitionsJson, states, alphabet, start using the definitions below. Serialize JSON text fields in the decoded shape shown below.
  2. Run the operation. Resolve input-format errors before interpreting an output.
  3. Read result.states, using the stated boundary, ordering, sign and absence conventions.

Validate the deterministic partial table and start-state membership, then explore outgoing transitions breadth first from start, deduplicating states on first discovery.1

Input fieldMeaning and unitsAccepted input
transitionsJsonJSON array of {from,symbol,to} literal string records, preserving transition indexes. Determinism is checked or audited as described above.Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply.
statesDistinct literal declared state IDs in bank order; full automaton operations require at least one.Dense list of at most 128 literal strings, each at most 8,192 UTF-16 units.
alphabetDistinct literal alphabet symbols in bank order; an empty alphabet is allowed.Dense list of at most 128 literal strings, each at most 8,192 UTF-16 units.
startLiteral starting state. Graph operations with a declared state bank require it to be present there.Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply.

These decoded structures show the examples inside JSON text fields. Supply their serialized JSON strings as input.

json
{
  "transitionsJson": [
    {
      "from": "a",
      "symbol": "x",
      "to": "b"
    },
    {
      "from": "b",
      "symbol": "x",
      "to": "b"
    }
  ]
}
Output fieldInterpretation
resultObject containing the fields below.
result.statesState trace or state inventory in the precise initial-state/discovery/bank order described above.
json
{
  "input": {
    "transitionsJson": "[{\"from\": \"a\", \"symbol\": \"x\", \"to\": \"b\"}, {\"from\": \"b\", \"symbol\": \"x\", \"to\": \"b\"}]",
    "states": [
      "a",
      "b",
      "c"
    ],
    "alphabet": [
      "x"
    ],
    "start": "a"
  },
  "output": {
    "result": {
      "states": [
        "a",
        "b"
      ]
    }
  }
}

Limitations and assumptions

  • The returned states follow breadth-first discovery in transition order, not declared bank order. Reachability is graph reachability over all available symbols.
  • Transition JSON is an array of {from,symbol,to} string records. Tools requiring a declared automaton use a nonempty distinct state bank and distinct alphabet, validate endpoints and symbols, and reject duplicate [from,symbol] keys. Trace-only tools validate keys without inferring a declared universe. No normalization or implicit sink is provided.
  • Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
  • Numeric outputs must remain finite and within safe-integer magnitude. Original record indexes and cell coordinates are zero-based; stated half-open ranges exclude their end.

Alternative or Complementary methods

Use endpoint and duplicate-key audits before transformations. Check completeness before complementing an accepting set, and preserve the declared alphabet, start-state convention and acceptance policy with exported tables.

References

  1. Tool behavior and example: DFA Reachable State Inventory — tool.io

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