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Subset Counterexample Single Witness Tool

Calculate subset counterexample single witness from explicit caller-supplied inputs.

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Description

Return counterexample when witness occurs in first and not in second.

A finite set records membership, while a multiset also records multiplicity. An ordered set adds an ordering rule, and an interval adds endpoint-closure choices. A witness for one element, a count budget, and equality of complete sets establish different facts.

Return counterexample when witness occurs in first and not in second.

When to use this tool

Use Subset Counterexample Single Witness when you need the stated finite-set, interval, multiplicity, membership, or ordering operation under the given equality convention.

How to use the tool and how it works

  1. Enter first, second, witness. Keep parallel arrays aligned. Use the units and conventions below.
  2. Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
  3. Read counterexample. Inspect counterexample before interpreting the associated values.

Return counterexample when witness occurs in first and not in second.1

Input fieldMeaning and unitsAccepted input
firstFirstRequired. Array of text; maximum UTF-16 length 8192; maximum items 256.
secondSecondRequired. Array of text; maximum UTF-16 length 8192; maximum items 256.
witnessWitnessRequired. Text; maximum UTF-16 length 8192.
Output fieldInterpretationReturned shape
counterexampleCounterexampleRequired. Boolean.
json
{
  "input": {
    "first": [
      "a",
      "b"
    ],
    "second": [
      "a"
    ],
    "witness": "b"
  },
  "output": {
    "counterexample": true
  }
}

Limitations and assumptions

  • A false result only says this particular witness fails; it does not prove the subset relation. Membership uses exact supplied strings without normalization or a complete set comparison.
  • The field tables state structural bounds; the mechanics also specify cross-field constraints. Malformed inputs and unsupported domains cause errors. A successful false flag, empty branch value, or zero placeholder has the meaning stated above and is distinct from an input error.
  • Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Signed zero is exported as zero.

Alternative or Complementary methods

Use a full set operation when one element or count cannot establish the required relation. Preserve the distinction between strings, typed scalar atoms, nested sets, ordered lists, and multisets.

References

  1. Calculation and input contract: set/subset-counterexample-single-witness — tool.io

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