A wavelet theory for local fields and related groups

Abstract

Let G be a locally compact abelian group with compact open subgroup H. The best known example of such a group is G = ℚp, the field of padic rational numbers (as a group under addition), which has compact open subgroup H = ℤp, the ring of padic integers. Classical wavelet theories, which require a non trivial discrete subgroup for translations, do not apply to G, which may not have such a subgroup. A wavelet theory is developed on G using coset representatives of the discrete quotient Ĝ/H⊥ to circumvent this limitation. Wavelet bases are constructed by means of an iterative method giving rise to socalled wavelet sets in the dual group Ĝ. Although the Haar and Shannon wavelets are naturally antipodal in the Euclidean setting, it is observed that their analogues for G are equivalent.