Past exam of the mathematics course of the University of Cambridge 2024 iii Paper 101 1 ii a Solution Created 2026-09-24 Updated 2026-09-25
The statement is true. If is generated by , there is a surjection . The right exactness of the tensor product of modules gives a surjectionA finite direct sum of Noetherian modules is Noetherian, and a quotient of a Noetherian module is Noetherian. Hence is Noetherian.
Past exam of the mathematics course of the University of Cambridge 2024 iii Paper 101 1 i Solution Created 2026-09-24 Updated 2026-09-25
An -module is Noetherian when every submodule is finitely generated, equivalently when every ascending chain of submodules stabilizes.
A free module is an -module with a basis: every element has a unique expression as a finite linear combination of basis elements.
A flat module is one for which the tensor functor is exact. Since tensor products are always right exact, it is equivalent to require that tensoring with preserve injections.
A projective module has the lifting property: for every surjection and every map , there is a map making the resulting triangle commute. Equivalently, is a direct summand of a free module.