A Mikhlin multiplier theory for free groups and amalgamated free products of von Neumann algebras
A Mikhlin multiplier theory for free groups and amalgamated free products of von Neumann algebras
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DOI:
10.1016/j.aim.2022.108394
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发表时间:
2022-07
影响因子:
1.7
通讯作者:
T. Mei;Éric Ricard;Quanhua Xu
中科院分区:
文献类型:
--
作者:
T. Mei;Éric Ricard;Quanhua Xu
We obtain a Mikhlin multiplier theory for the nonabelian free groups. Let F∞ be a free group on infinite many generators {g 1, g 2,⋯}. Given d≥ 1 and a bounded symbol m on Z d satisfying the classical Mikhlin condition, the linear map M m: C [F∞]→ C [F∞] defined by λ (g)↦ m (k 1,⋯, k d) λ (g) for g= g i 1 k 1⋯ g i n k n∈ F∞ in reduced form (with k l= 0 in m (k 1,⋯, k d) for l> n), extends to a completely bounded map on L p (F ˆ∞) for all 1< p<∞, where F ˆ∞ is the group von Neumann algebra of F∞. In the process, we establish a platform to transfer L p-completely bounded maps on tensor products of von Neumann algebras to L p-completely bounded maps on the corresponding amalgamated free products. A similar result holds for any free product of discrete groups.