T261.json

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{
  "Title": "Hall\u2013Littlewood polynomials $P_\\lambda(x_1,\\dots,x_n;t)$",
  "Definition": "The Hall\u2013Littlewood polynomial $P_\\lambda(x_1,\\dots,x_n;t)$ CITE{Wiki} is Macdonald's $P$-normalised Hall\u2013Littlewood symmetric polynomial CITE{Macdonald}, given by CITE{formula-symmetrization} for a partition $\\lambda$ with at most $n$ parts.",
  "Keywords": [
    "Hall-Littlewood symmetric functions",
    "Hall Littlewood polynomials",
    "Macdonald Hall-Littlewood polynomials"
  ],
  "Tags": [
    "polynomial",
    "combinatorics",
    "algebra",
    "bases for symmetric polynomials"
  ],
  "Parameters": {
    "n": {
      "type": "Z",
      "title": "number of variables",
      "display": "$n$",
      "constraints": "a positive integer"
    },
    "lambda": {
      "type": "Symbolic",
      "display": "$\\lambda$",
      "constraints": "a partition with at most $n$ parts",
      "title": "shape"
    }
  },
  "Comments": {
    "notation": "The partition is written as its parts, largest first, separated by commas: $2,1,1$ is the partition $(2,1,1)$ of $4$.",
    "convention": "$t$ is an indeterminate, and $\\lambda$ is padded with zeros to length $n$ in CITE{formula-symmetrization}. In this $P$ normalisation, the coefficient of HREF{Monomial_symmetric_polynomials}[the monomial symmetric polynomial] $m_\\lambda$ is $1$, and the other monomial terms are indexed by partitions $\\mu$ lower than $\\lambda$ in dominance order. The $Q_\\lambda$ normalisation multiplies $P_\\lambda$ by a factor depending on $\\lambda$ and $t$. The transformed Hall\u2013Littlewood polynomial $Q'_\\lambda(x;t)=Q_\\lambda[x/(1-t);t]$ is not a scalar multiple of $P_\\lambda$ in general."
  },
  "Formulas": {
    "formula-symmetrization": "$P_\\lambda(x_1,\\dots,x_n;t)=v_\\lambda(t)^{-1}\\sum_{w\\in S_n} w\\left(x_1^{\\lambda_1}\\cdots x_n^{\\lambda_n} \\prod_{1\\leq i<j\\leq n}\\frac{x_i-tx_j}{x_i-x_j}\\right)$, where $v_\\lambda(t)=\\prod_{r\\geq0}\\prod_{j=1}^{m_r(\\lambda)}(1-t^j)/(1-t)$, $m_r(\\lambda)$ is the number of parts of $\\lambda$ equal to $r$, $\\ell(\\lambda)$ is the number of nonzero parts, and $m_0(\\lambda)=n-\\ell(\\lambda)$ counts the zeros added by padding.",
    "formula-schur": "$P_\\lambda(x;0)=s_\\lambda(x)$, HREF{Schur_polynomials}[the Schur polynomial].",
    "formula-monomial": "$P_\\lambda(x;1)=m_\\lambda(x)$, HREF{Monomial_symmetric_polynomials}[the monomial symmetric polynomial].",
    "formula-transition": "$s_\\lambda(x)=\\sum_\\mu K_{\\lambda\\mu}(t)P_\\mu(x;t)$, where the sum is over partitions $\\mu$ of $|\\lambda|$ with at most $n$ parts and $K_{\\lambda\\mu}(t)$ is HREF{T259}[the Kostka-Foulkes polynomial]."
  },
  "Programs": {
    "program-sage": {
      "language": "Sage",
      "code": "from sage.all import QQ, PolynomialRing, SymmetricFunctions\n\nT = PolynomialRing(QQ, 't')\nP = SymmetricFunctions(T.fraction_field()).hall_littlewood().P()\ngrouped = P([3, 2]).expand(4, alphabet=['x1', 'x2', 'x3', 'x4'])\n\n# Sage groups coefficients in t; this writes the same polynomial\n# expanded over QQ[x1, x2, x3, x4, t], as the table does.\nR = PolynomialRing(QQ, ['x1', 'x2', 'x3', 'x4', 't'])\nprint(R(str(grouped)))"
    }
  },
  "Similar tables": [
    {
      "table": "HREF{Schur_polynomials}[Schur polynomials]",
      "relation": "are the $t=0$ specialization"
    },
    {
      "table": "HREF{Monomial_symmetric_polynomials}[monomial symmetric polynomials]",
      "relation": "are the $t=1$ specialization"
    },
    {
      "table": "HREF{T259}[Kostka-Foulkes polynomials]",
      "relation": "are the transition coefficients from Schur polynomials to this Hall\u2013Littlewood $P$ basis"
    }
  ],
  "Links": {
    "Wiki": {
      "title": "Wikipedia: Hall-Littlewood polynomials",
      "url": "https://en.wikipedia.org/wiki/Hall%E2%80%93Littlewood_polynomials"
    },
    "SageHallLittlewood": {
      "title": "SageMath: Hall-Littlewood symmetric functions",
      "url": "https://doc.sagemath.org/html/en/reference/combinat/sage/combinat/sf/hall_littlewood.html"
    }
  },
  "References": {
    "Macdonald": {
      "bib": "I. G. Macdonald, Symmetric Functions and Hall Polynomials, second ed., The Clarendon Press, Oxford University Press, New York, 1995.",
      "mr": "1354144"
    }
  },
  "Data properties": {
    "type": "Z[]",
    "rigour": "exact",
    "complete": "no",
    "complete-note": "it holds every $P_\\lambda$ with $1\\leq n\\leq4$, $1\\leq|\\lambda|\\leq4$, and $\\ell(\\lambda)\\leq n$; extending the same rectangle to $n=5$ would make $P_{(4)}$ 2493 characters long, while extending to $|\\lambda|=5$ at $n=4$ would make $P_{(5)}$ 2114 characters long",
    "rigour details": "Every entry is an exact polynomial with integer coefficients. The generator computes Macdonald's symmetrization formula in the fraction field of $\\mathbb{Z}[x_1,\\dots,x_n,t]$ and refuses an entry unless the denominator cancels.\nBefore the values were written, every entry was compared with Sage's Hall-Littlewood $P$ basis CITE{SageHallLittlewood}. The same values were checked at $t=0$ against HREF{Schur_polynomials}[the Schur polynomials], at $t=1$ against HREF{Monomial_symmetric_polynomials}[the monomial symmetric polynomials], and in the transition identity with HREF{T259}[the Kostka-Foulkes polynomials]."
  },
  "Display properties": {
    "number-header": "$P_\\lambda(x_1,\\dots,x_n;t)$"
  },
  "Numbers": {
    "1": {
      "1": "x1",
      "2": "x1^2",
      "3": "x1^3",
      "4": "x1^4"
    },
    "2": {
      "1": "x1 + x2",
      "2": "-x1*x2*t + x1^2 + x1*x2 + x2^2",
      "1,1": "x1*x2",
      "3": "-x1^2*x2*t - x1*x2^2*t + x1^3 + x1^2*x2 + x1*x2^2 + x2^3",
      "2,1": "x1^2*x2 + x1*x2^2",
      "4": "-x1^3*x2*t - x1^2*x2^2*t - x1*x2^3*t + x1^4 + x1^3*x2 + x1^2*x2^2 + x1*x2^3 + x2^4",
      "3,1": "-x1^2*x2^2*t + x1^3*x2 + x1^2*x2^2 + x1*x2^3",
      "2,2": "x1^2*x2^2"
    },
    "3": {
      "1": "x1 + x2 + x3",
      "2": "-x1*x2*t - x1*x3*t - x2*x3*t + x1^2 + x1*x2 + x2^2 + x1*x3 + x2*x3 + x3^2",
      "1,1": "x1*x2 + x1*x3 + x2*x3",
      "3": "x1*x2*x3*t^2 - x1^2*x2*t - x1*x2^2*t - x1^2*x3*t - 2*x1*x2*x3*t - x2^2*x3*t - x1*x3^2*t - x2*x3^2*t + x1^3 + x1^2*x2 + x1*x2^2 + x2^3 + x1^2*x3 + x1*x2*x3 + x2^2*x3 + x1*x3^2 + x2*x3^2 + x3^3",
      "2,1": "-x1*x2*x3*t^2 - x1*x2*x3*t + x1^2*x2 + x1*x2^2 + x1^2*x3 + 2*x1*x2*x3 + x2^2*x3 + x1*x3^2 + x2*x3^2",
      "1,1,1": "x1*x2*x3",
      "4": "x1^2*x2*x3*t^2 + x1*x2^2*x3*t^2 + x1*x2*x3^2*t^2 - x1^3*x2*t - x1^2*x2^2*t - x1*x2^3*t - x1^3*x3*t - 2*x1^2*x2*x3*t - 2*x1*x2^2*x3*t - x2^3*x3*t - x1^2*x3^2*t - 2*x1*x2*x3^2*t - x2^2*x3^2*t - x1*x3^3*t - x2*x3^3*t + x1^4 + x1^3*x2 + x1^2*x2^2 + x1*x2^3 + x2^4 + x1^3*x3 + x1^2*x2*x3 + x1*x2^2*x3 + x2^3*x3 + x1^2*x3^2 + x1*x2*x3^2 + x2^2*x3^2 + x1*x3^3 + x2*x3^3 + x3^4",
      "3,1": "-x1^2*x2^2*t - 2*x1^2*x2*x3*t - 2*x1*x2^2*x3*t - x1^2*x3^2*t - 2*x1*x2*x3^2*t - x2^2*x3^2*t + x1^3*x2 + x1^2*x2^2 + x1*x2^3 + x1^3*x3 + 2*x1^2*x2*x3 + 2*x1*x2^2*x3 + x2^3*x3 + x1^2*x3^2 + 2*x1*x2*x3^2 + x2^2*x3^2 + x1*x3^3 + x2*x3^3",
      "2,2": "-x1^2*x2*x3*t - x1*x2^2*x3*t - x1*x2*x3^2*t + x1^2*x2^2 + x1^2*x2*x3 + x1*x2^2*x3 + x1^2*x3^2 + x1*x2*x3^2 + x2^2*x3^2",
      "2,1,1": "x1^2*x2*x3 + x1*x2^2*x3 + x1*x2*x3^2"
    },
    "4": {
      "1": "x1 + x2 + x3 + x4",
      "2": "-x1*x2*t - x1*x3*t - x2*x3*t - x1*x4*t - x2*x4*t - x3*x4*t + x1^2 + x1*x2 + x2^2 + x1*x3 + x2*x3 + x3^2 + x1*x4 + x2*x4 + x3*x4 + x4^2",
      "1,1": "x1*x2 + x1*x3 + x2*x3 + x1*x4 + x2*x4 + x3*x4",
      "3": "x1*x2*x3*t^2 + x1*x2*x4*t^2 + x1*x3*x4*t^2 + x2*x3*x4*t^2 - x1^2*x2*t - x1*x2^2*t - x1^2*x3*t - 2*x1*x2*x3*t - x2^2*x3*t - x1*x3^2*t - x2*x3^2*t - x1^2*x4*t - 2*x1*x2*x4*t - x2^2*x4*t - 2*x1*x3*x4*t - 2*x2*x3*x4*t - x3^2*x4*t - x1*x4^2*t - x2*x4^2*t - x3*x4^2*t + x1^3 + x1^2*x2 + x1*x2^2 + x2^3 + x1^2*x3 + x1*x2*x3 + x2^2*x3 + x1*x3^2 + x2*x3^2 + x3^3 + x1^2*x4 + x1*x2*x4 + x2^2*x4 + x1*x3*x4 + x2*x3*x4 + x3^2*x4 + x1*x4^2 + x2*x4^2 + x3*x4^2 + x4^3",
      "2,1": "-x1*x2*x3*t^2 - x1*x2*x4*t^2 - x1*x3*x4*t^2 - x2*x3*x4*t^2 - x1*x2*x3*t - x1*x2*x4*t - x1*x3*x4*t - x2*x3*x4*t + x1^2*x2 + x1*x2^2 + x1^2*x3 + 2*x1*x2*x3 + x2^2*x3 + x1*x3^2 + x2*x3^2 + x1^2*x4 + 2*x1*x2*x4 + x2^2*x4 + 2*x1*x3*x4 + 2*x2*x3*x4 + x3^2*x4 + x1*x4^2 + x2*x4^2 + x3*x4^2",
      "1,1,1": "x1*x2*x3 + x1*x2*x4 + x1*x3*x4 + x2*x3*x4",
      "4": "-x1*x2*x3*x4*t^3 + x1^2*x2*x3*t^2 + x1*x2^2*x3*t^2 + x1*x2*x3^2*t^2 + x1^2*x2*x4*t^2 + x1*x2^2*x4*t^2 + x1^2*x3*x4*t^2 + 3*x1*x2*x3*x4*t^2 + x2^2*x3*x4*t^2 + x1*x3^2*x4*t^2 + x2*x3^2*x4*t^2 + x1*x2*x4^2*t^2 + x1*x3*x4^2*t^2 + x2*x3*x4^2*t^2 - x1^3*x2*t - x1^2*x2^2*t - x1*x2^3*t - x1^3*x3*t - 2*x1^2*x2*x3*t - 2*x1*x2^2*x3*t - x2^3*x3*t - x1^2*x3^2*t - 2*x1*x2*x3^2*t - x2^2*x3^2*t - x1*x3^3*t - x2*x3^3*t - x1^3*x4*t - 2*x1^2*x2*x4*t - 2*x1*x2^2*x4*t - x2^3*x4*t - 2*x1^2*x3*x4*t - 3*x1*x2*x3*x4*t - 2*x2^2*x3*x4*t - 2*x1*x3^2*x4*t - 2*x2*x3^2*x4*t - x3^3*x4*t - x1^2*x4^2*t - 2*x1*x2*x4^2*t - x2^2*x4^2*t - 2*x1*x3*x4^2*t - 2*x2*x3*x4^2*t - x3^2*x4^2*t - x1*x4^3*t - x2*x4^3*t - x3*x4^3*t + x1^4 + x1^3*x2 + x1^2*x2^2 + x1*x2^3 + x2^4 + x1^3*x3 + x1^2*x2*x3 + x1*x2^2*x3 + x2^3*x3 + x1^2*x3^2 + x1*x2*x3^2 + x2^2*x3^2 + x1*x3^3 + x2*x3^3 + x3^4 + x1^3*x4 + x1^2*x2*x4 + x1*x2^2*x4 + x2^3*x4 + x1^2*x3*x4 + x1*x2*x3*x4 + x2^2*x3*x4 + x1*x3^2*x4 + x2*x3^2*x4 + x3^3*x4 + x1^2*x4^2 + x1*x2*x4^2 + x2^2*x4^2 + x1*x3*x4^2 + x2*x3*x4^2 + x3^2*x4^2 + x1*x4^3 + x2*x4^3 + x3*x4^3 + x4^4",
      "3,1": "x1*x2*x3*x4*t^3 + x1*x2*x3*x4*t^2 - x1^2*x2^2*t - 2*x1^2*x2*x3*t - 2*x1*x2^2*x3*t - x1^2*x3^2*t - 2*x1*x2*x3^2*t - x2^2*x3^2*t - 2*x1^2*x2*x4*t - 2*x1*x2^2*x4*t - 2*x1^2*x3*x4*t - 5*x1*x2*x3*x4*t - 2*x2^2*x3*x4*t - 2*x1*x3^2*x4*t - 2*x2*x3^2*x4*t - x1^2*x4^2*t - 2*x1*x2*x4^2*t - x2^2*x4^2*t - 2*x1*x3*x4^2*t - 2*x2*x3*x4^2*t - x3^2*x4^2*t + x1^3*x2 + x1^2*x2^2 + x1*x2^3 + x1^3*x3 + 2*x1^2*x2*x3 + 2*x1*x2^2*x3 + x2^3*x3 + x1^2*x3^2 + 2*x1*x2*x3^2 + x2^2*x3^2 + x1*x3^3 + x2*x3^3 + x1^3*x4 + 2*x1^2*x2*x4 + 2*x1*x2^2*x4 + x2^3*x4 + 2*x1^2*x3*x4 + 3*x1*x2*x3*x4 + 2*x2^2*x3*x4 + 2*x1*x3^2*x4 + 2*x2*x3^2*x4 + x3^3*x4 + x1^2*x4^2 + 2*x1*x2*x4^2 + x2^2*x4^2 + 2*x1*x3*x4^2 + 2*x2*x3*x4^2 + x3^2*x4^2 + x1*x4^3 + x2*x4^3 + x3*x4^3",
      "2,2": "x1*x2*x3*x4*t^3 - x1^2*x2*x3*t - x1*x2^2*x3*t - x1*x2*x3^2*t - x1^2*x2*x4*t - x1*x2^2*x4*t - x1^2*x3*x4*t - 3*x1*x2*x3*x4*t - x2^2*x3*x4*t - x1*x3^2*x4*t - x2*x3^2*x4*t - x1*x2*x4^2*t - x1*x3*x4^2*t - x2*x3*x4^2*t + x1^2*x2^2 + x1^2*x2*x3 + x1*x2^2*x3 + x1^2*x3^2 + x1*x2*x3^2 + x2^2*x3^2 + x1^2*x2*x4 + x1*x2^2*x4 + x1^2*x3*x4 + 2*x1*x2*x3*x4 + x2^2*x3*x4 + x1*x3^2*x4 + x2*x3^2*x4 + x1^2*x4^2 + x1*x2*x4^2 + x2^2*x4^2 + x1*x3*x4^2 + x2*x3*x4^2 + x3^2*x4^2",
      "2,1,1": "-x1*x2*x3*x4*t^3 - x1*x2*x3*x4*t^2 - x1*x2*x3*x4*t + x1^2*x2*x3 + x1*x2^2*x3 + x1*x2*x3^2 + x1^2*x2*x4 + x1*x2^2*x4 + x1^2*x3*x4 + 3*x1*x2*x3*x4 + x2^2*x3*x4 + x1*x3^2*x4 + x2*x3^2*x4 + x1*x2*x4^2 + x1*x3*x4^2 + x2*x3*x4^2",
      "1,1,1,1": "x1*x2*x3*x4"
    }
  }
}