User:Zhongmou Zhang/sandbox

Section
editable text $$\require{AMScd}\begin{CD} 0 @>>> \prod_{i > 0}\mathbb{Z} @>{f(e_{ij})=p^jf(e_i)-f(e_{i-j})}>> \prod_{i\ge j>0} \mathbb{Z}\\ @VVV @VVV @VVV \\ 0 @>>> \prod_{i \ge 0}\mathbb{Z} @>{f(e_{ij})=p^jf(e_i)-f(e_{i-j})}>> \prod_{i\ge j>0} \mathbb{Z} \\ @VVV @VVV @VVV \\ \mathbb{Z} @>\text{id}>> \mathbb{Z} @>0>>0 \end{CD} $$ $$\prod_{i\ge j>0}$$