grandes-ecoles 2023 QI.2

grandes-ecoles · France · x-ens-maths-d__mp Groups Subgroup and Normal Subgroup Properties
Let $A$ be a commutative ring. Let $S _ { 1 }$ and $S _ { 2 }$ be two subsets of $A$ such that $S _ { 1 } \subset \mathcal { A } \left( S _ { 2 } \right)$. Show that $\mathcal { A } \left( S _ { 1 } \right) \subset \mathcal { A } \left( S _ { 2 } \right)$.
Let $A$ be a commutative ring. Let $S _ { 1 }$ and $S _ { 2 }$ be two subsets of $A$ such that $S _ { 1 } \subset \mathcal { A } \left( S _ { 2 } \right)$. Show that $\mathcal { A } \left( S _ { 1 } \right) \subset \mathcal { A } \left( S _ { 2 } \right)$.