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Combinatorics: Integer Partition Durfee Size Tool

Compute the Durfee-square side of one descending integer partition, not a partition-number solver.

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Description

Return an integer partition's Durfee-square size.

Partitions, permutations and circular words use distinct encodings and symmetry conventions. Parity, block bounds and orbit-size identities can follow from supplied counts without verifying a complete object or identifying its actual symmetry.

Return an integer partition's Durfee-square size.

When to use this tool

Use Combinatorics: Integer Partition Durfee Size when checking the stated partition, permutation or rotation/reflection convention.

How to use the tool and how it works

  1. Enter parts. 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 result. Expand result to inspect the returned fields.

Return an integer partition's Durfee-square size. Require positive nonincreasing whole parts; count indexes j with parts[j] >= j+1.1

Input fieldMeaning and unitsAccepted input
partsPartsRequired. Array of finite number. Implementation limit: 128 items.
Output fieldInterpretationReturned shape
resultReturned calculated value or nested object under the stated output convention.Required. Object.
result.durfeeSizeDurfee SizeCalculated result member: number.
json
{
  "input": {
    "parts": [
      4,
      3,
      1
    ]
  },
  "output": {
    "result": {
      "durfeeSize": 2
    }
  }
}

Limitations and assumptions

  • Empty partition gives zero; this checks the supplied Ferrers shape rather than generating or counting partitions.
  • Outputs are nested inside result. Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
  • 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. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Validate the complete combinatorial object and its action/labeling convention before applying whole-object enumeration, ranking or symmetry conclusions.

References

  1. Calculation and input contract: combinatorics/integer-partition-durfee-size — tool.io

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