The groups Sp(1;R), O(3;4) form a dual pair in the sense of Howe. This leads to a correspondence of irreducible unitary representations between the double connected cover of Sp(1;R) and some irreducible unitary representations of O(3;4). By a property of double transitivity, Rallis & Schiffmann showed that the restriction of the resulting representation to G2 remains irreducible, but don't compute the characters of these representations. Neither do they compute the lowest term of the expansion of such a character, which should be the Fourier transform of an orbital integral corresponding to a...
The groups Sp(1;R), O(3;4) form a dual pair in the sense of Howe. This leads to a correspondence of irreducible unitary representations between the do...
