If $s_n $ and $t_k $ satisfy the conditions
I) $0 ≤ s_n≤ t_k $, if $n <2^k $
II) $2s_n≥ t_k≥ 0 $, if $n>2^k $
Can we conclude that $s_n $ converges if and only if $t_n $ converges?
If $s_n $ and $t_k $ satisfy the conditions
I) $0 ≤ s_n≤ t_k $, if $n <2^k $
II) $2s_n≥ t_k≥ 0 $, if $n>2^k $
Can we conclude that $s_n $ converges if and only if $t_n $ converges?
For all $n\in\mathbb N$, consider $$0\leq s_n\leq t_{\lfloor \log_2 n\rfloor+1}$$ $$0\leq t_n\leq 2s_{2^n +1}$$ and if one of two sequences converges, the other does too.