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If one restricts an irreducible representation rc">rmulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0097316516300024&_mathId=si1.gif&_user=111111111&_pii=S0097316516300024&_rdoc=1&_issn=00973165&md5=53ceb952f36d1526ffbcb22944671e13" title="Click to view the MathML source">Vλr hidden"> of rc">rmulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0097316516300024&_mathId=si2.gif&_user=111111111&_pii=S0097316516300024&_rdoc=1&_issn=00973165&md5=f2c82166183af2d106b5ebdfe1e8987a" title="Click to view the MathML source">GL2nr hidden"> to the orthogonal group (respectively the symplectic group), the trivial representation appears with multiplicity one if and only if all parts of λ are even (resp. the conjugate partition rc">rmulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0097316516300024&_mathId=si3.gif&_user=111111111&_pii=S0097316516300024&_rdoc=1&_issn=00973165&md5=775aac74887aa76245c138f0218b933d" title="Click to view the MathML source">λ′r hidden"> is even). One can rephrase this statement as an integral identity involving Schur functions, the corresponding characters. Rains and Vazirani considered rc">rmulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0097316516300024&_mathId=si4.gif&_user=111111111&_pii=S0097316516300024&_rdoc=1&_issn=00973165&md5=ba3cfb11e2d1ff464b3514d2cfb1bf4a" title="Click to view the MathML source">q,tr hidden">-generalizations of such integral identities, and proved them using affine Hecke algebra techniques. In a recent paper, we investigated the rc">rmulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0097316516300024&_mathId=si25.gif&_user=111111111&_pii=S0097316516300024&_rdoc=1&_issn=00973165&md5=9986c95a941df88c3fee596745dcd08f" title="Click to view the MathML source">q=0r hidden"> limit (Hall–Littlewood), and provided direct combinatorial arguments for these identities; this approach led to various generalizations and a finite-dimensional analog of a recent summation identity of Warnaar. In this paper, we reformulate some of these results using p-adic representation theory; this parallels the representation-theoretic interpretation in the Schur case. The nonzero values of the identities are interpreted as certain p-adic measure counts. This approach provides a p-adic interpretation of these identities (and a new identity), as well as independent proofs. As an application, we obtain a new Littlewood summation identity that generalizes a classical result due to Littlewood and Macdonald. Finally, our p-adic method also leads to a generalized integral identity in terms of Littlewood–Richardson coefficients and Hall polynomials.