We prove two identities of Hall-Littlewood polynomials, which appeared
recently in a paper by two of the authors. We also conjecture, and in some
cases prove, new identities which relate infinite sums of symmetric polynomials
and partition functions associated with symmetry classes of alternating sign
matrices. These identities generalize those already found in our earlier paper,
via the introduction of additional parameters. The left hand side of each of
our identities is a simple refinement of a relevant Cauchy or Littlewood
identity. The right hand side of each identity is (one of the two factors
present in) the partition function of the six-vertex model on a relevant
domain.Comment: 34 pages, 14 figure