The Congruence Subgroup Problem for $SL(n,Z)$

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Daniel Shenfeld, Princeton University
Fine Hall 314

The group $SL(n, k)$ ($k$ a field) is simple modulo its center, but for a ring $A$, $SL(n, A)$ is not: the kernels of the maps $SL(n,A)\rightarrow SL(n,A/I)$ (\$I