I want to figure out question 1.6 in Wheenden and Zygmund (2015)
The question is compare $\limsup_{k\to\infty} a_k$ with $\limsup(-\infty, a_k)$
(no more condition...)
I think $\limsup a_k \leq \limsup(-\infty, a_k)$
If $\limsup a_k$ is $+\infty$ or $a<\infty$ then equality holds.
If $\limsup a_k$ is $-\infty$ then inequality holds.
But I am not sure whether I'm right or not...