I need help solving the following problem:
Let M,N be differentiable manifolds, and f\in C^\infty(M,N). We say that the fields X\in \mathfrak{X}(M) and Y \in \mathfrak{X}(N) are f-related if and only if f_{*p}(X(p))=Y_{f(p)} for all p\in M.
Prove that:
(a) X and Y are f-related if and only if...