A result in asymptotic theory says the following: Let $Y$ be a real random variable with full support and $E(|Y|)<\infty$. Assume that: $$ (A)\quad \lim_{y\rightarrow \infty} \frac{\Pr(Y\geq y)}{\Pr(Y\geq \kappa h(y))}=1 $$ for some $\kappa>0$ and function $h$ such that $\lim_{y\rightarrow \infty} h'(y)=1 $. Then, $\kappa=1$. Could you help me understand:**(1)** How to interpret $(A)$; **(2)** How to interpret the result that $\kappa$ must be 1; **(3)** Why would you expect this result to intuitively hold or not hold? _________ ***Thoughts.*** Regarding **(1)**: The limiting condition says that $ h(y) =\alpha+ y $ in the limit. Then, I think it holds that $$ (B)\quad \lim_{y \rightarrow \infty} \Pr(Y \geq y) = \lim_{y \rightarrow \infty} \Pr(Y \geq \kappa h(y)) = 0. $$ Assumption $(A)$ is stronger than $(B)$, because I think $(A)$ says that $\Pr(Y \geq y)$ and $\Pr(Y \geq \kappa h(y))$ go to zero at the same rate (but I am not sure here about this). Regarding **(2)**: Somehow, this result suggests that if $(A)$ holds, then $h$ can shift and rescale $y$ (in the limit), but the multiplicative constant $\kappa$ in front of $h$ must be one. Is this a correct interpretation of the result? Regarding **(3)**: I have zero intuition. If my interpretation of the result is correct (see above), why can $h$ be anything and $\kappa$ must instead be one?