2 problems

Let $R$ be a ring and let $M$ be an $R$-module. A flat cover of $M$ is a flat $R$-module equipped with a cover morphism onto $M$. Enochs's flat cover conjecture. Every $R$-module h…

Let $S$ be a monoid, and write $\operatorname{Act}$-$S$ for the category of right $S$-acts. The monoid $S$ is right-reversible when any two principal right ideals intersect. Let…