Source: https://guthlabs.ai/docs/instruments/finite-state-machine-simulator/

instrument / verified-clean

# Finite State Machine Simulator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/finite-state-machine-simulator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/finite-state-machine-simulator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/finite-state-machine-simulator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/finite-state-machine-simulator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Computing & Information

**Tranche**: tranche-6

**Evidence ID**: t6-052

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The core DFA and non-epsilon-NFA algorithms are standard. The instrument needs an explicit contract for epsilon transitions, incomplete transition tables, invalid input symbols, NFA acceptance semantics, and deterministic rendering of subset traces before it can receive an unqualified PASS.

### Formula and scope findings

- The DFA rule δ(q,a) is standard and correct, provided δ is deterministic and total for every state and input symbol; the specification does not state how missing transitions are handled.

- NFA simulation by propagating subsets of states is standard and correct for NFAs without epsilon transitions.

- If epsilon transitions are supported, subset construction must apply epsilon-closure before processing the first symbol, after every symbol, and for final acceptance; this is not specified.

- The specification does not define whether an NFA accepts when any state in the final reachable subset is accepting, although that is the standard rule.

### Unit assumptions

- There are no physical units; states and alphabet symbols are discrete identifiers.

- Input symbols must be matched exactly as declared in the alphabet; case sensitivity, Unicode normalization, and treatment of undeclared symbols should be specified.

- The empty input string is a valid input and is accepted exactly when the start state, or the epsilon-closure of the start state for an epsilon-NFA, contains an accepting state.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The specification does not define behavior for an input symbol outside the declared alphabet or for an undefined transition. Such an input makes δ undefined, so an implementation that silently continues, invents a state, or returns a normal verdict would break the stated simulation model.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "type": "DFA",
    "states": [
      "q_even",
      "q_odd"
    ],
    "alphabet": [
      "0",
      "1"
    ],
    "transitions": {
      "q_even": {
        "0": "q_even",
        "1": "q_odd"
      },
      "q_odd": {
        "0": "q_odd",
        "1": "q_even"
      }
    },
    "start_state": "q_even",
    "accept_states": [
      "q_even"
    ],
    "input_string": "1010"
  },
  "expected_outputs": {
    "verdict": "accepted",
    "state_trace": [
      "q_even",
      "q_odd",
      "q_odd",
      "q_even",
      "q_even"
    ]
  },
  "working": "Start q_even. Read 1: δ(q_even,1)=q_odd. Read 0: δ(q_odd,0)=q_odd. Read 1: δ(q_odd,1)=q_even. Read 0: δ(q_even,0)=q_even. Final state q_even is accepting, so the result is accepted."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche6/tranche6-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`