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5 votes
1 answer
156 views

The inverse limit of a sequence of ring surjections commutes with taking difference subsets of the respective units & gluing in some primes?

Define $R_n := \Bbb{Z}/p_n\#$ the ring of integers modulo primorial $p_n\# = p_n p_{n-1} \cdots p_1$. Let $U_n$ denote the group of units modulo $p_n\#$ in these rings. Then if $f_{n,n+1}: \Bbb{Z}/p_{...
Daniel Donnelly's user avatar
4 votes
2 answers
366 views

Canonical presentation of pro-modules over pro-rings

Let $A = (\dotsc \twoheadrightarrow A_2 \twoheadrightarrow A_1 \twoheadrightarrow A_0)$ be a (commutative) pro-ring with surjective transition maps. Consider the category $\mathcal{M} := \varprojlim_i ...
Martin Brandenburg's user avatar