错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Zak Transform Associated with the Weyl Transform and the System of Twisted Translates on \(\mathbb {R}^{2n}\)

  • Radha Ramakrishnan,
  • Rabeetha Velsamy

摘要

We introduce the Zak transform on \(L^{2}(\mathbb {R}^{2n})\) L 2 ( R 2 n ) associated with the Weyl transform. By making use of this transform, we define a bracket map and prove that the system of twisted translates \(\{{T_{(k,l)}^t}{\phi }: k,l\in \mathbb {Z}^{n}\}\) { T ( k , l ) t ϕ : k , l Z n } is a frame sequence iff \(0<A\le \left[ {\phi },{\phi }\right] (\xi ,\xi ^{'})\le B<\infty ,\) 0 < A ϕ , ϕ ( ξ , ξ ) B < , for a.e \((\xi ,\xi ^{'})\in \Omega _{{\phi }},\) ( ξ , ξ ) Ω ϕ , where \(\Omega _{{\phi }}=\{({\xi },{\xi ^{'}})\in {\mathbb {T}^{n}}\times {\mathbb {T}^{n}}: \left[ {\phi },{\phi }\right] (\xi ,\xi ^{'})\ne 0\}\) Ω ϕ = { ( ξ , ξ ) T n × T n : ϕ , ϕ ( ξ , ξ ) 0 } . We also prove a similar result for the system \(\{{T_{(k,l)}^t}{\phi }: k,l\in \mathbb {Z}^{n}\}\) { T ( k , l ) t ϕ : k , l Z n } to be a Riesz sequence. For a given function belonging to the principal twisted shift-invariant space \(V^{t}({\phi })\) V t ( ϕ ) , we find a necessary and sufficient condition for the existence of a canonical biorthogonal function. Further, we obtain a characterization for the system \(\{{T_{(k,l)}^t}{\phi }: k,l\in \mathbb {Z}\}\) { T ( k , l ) t ϕ : k , l Z } to be a Schauder basis for \(V^{t}({\phi })\) V t ( ϕ ) in terms of a Muckenhoupt \(\mathcal {A}_{2}\) A 2 weight function.