An explicit spine for the Picard modular group over the Gaussian integers
نویسندگان
چکیده
Let Γ \D be an arithmetic quotient of a symmetric space of non-compact type. A spine D0 is a Γ -equivariant deformation retraction of D with dimension equal to the virtual cohomological dimension of Γ . We explicitly construct a spine for the case of Γ = SU(2,1;Z[i]). The spine is then used to compute the cohomology of Γ \D with various local coefficients. © 2007 Elsevier Inc. All rights reserved. MSC: primary 11F57; secondary 53C35
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تاریخ انتشار 2007