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Polynomial Truncated Coefficient Product

Return polynomial product coefficients only through an explicit maximum power, equivalent to reduction modulo x^(degree+1); no coefficient rounding.

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Description

Return polynomial product coefficients only through an explicit maximum power, equivalent to reduction modulo x^(degree+1); no coefficient rounding.

A coefficient list here is constant-first: index j multiplies x to power j. Thus [1, 2, 3] represents 1 + 2x + 3x². Trailing list zeros are high-power zeros; stored length can differ from mathematical degree, and the zero polynomial needs a separate degree convention.

Return polynomial product coefficients only through an explicit maximum power, equivalent to reduction modulo x^(degree+1); no coefficient rounding.

When to use this tool

Use this tool to return polynomial product coefficients only through an explicit maximum power, equivalent to reduction modulo x^(degree+1); no coefficient rounding.

How to use the tool and how it works

  1. Enter left, right, degree using the field definitions below.
  2. Run the operation. Correct input errors before interpreting an output.
  3. Read result.coefficients. Use the ordering, boundary rules and absence conditions described below.

Convolve the two coefficient lists, normalize trailing high-power zeros, then retain powers zero through the requested degree.1

Input fieldMeaning and unitsAccepted input
leftLeft factor’s constant-first coefficient list.Dense list of at most 128 finite numbers; integer/shape constraints above also apply.
rightRight factor’s constant-first coefficient list.Dense list of at most 128 finite numbers; integer/shape constraints above also apply.
degreeNonnegative degree used for the requested output extent or truncation.A finite safe integer within the operation’s stated bounds.
Output fieldInterpretation
resultObject containing the named fields below.
result.coefficientsResult coefficients in ascending power order.
json
{
  "input": {
    "left": [
      1,
      2
    ],
    "right": [
      3,
      4
    ],
    "degree": 1
  },
  "output": {
    "result": {
      "coefficients": [
        3,
        10
      ]
    }
  }
}

Limitations and assumptions

  • The full convolution must fit the 128-coefficient limit before truncation occurs.
  • Coefficient lists use ascending powers and ordinary floating-point arithmetic. Nonempty input is required; individual operations impose tighter size limits. The tool does not attach or check physical units for x and its coefficients.
  • Every declared top-level input field is required and unexpected fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
  • Numeric outputs must be finite and no larger in absolute magnitude than the safe-integer limit; operations returning exact large integers use decimal text. Positions are zero-based and spans end exclusively unless the operation explicitly states a different convention.

Alternative or Complementary methods

Check coefficient order before importing data from another algebra library. Use separate root-finding or symbolic algebra methods when an operation requires more than the stated coefficient transformation.

References

  1. Tool behavior and example: Polynomial Truncated Coefficient Product — tool.io

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