We regret to report that our paper, entitled ``On the Value of Look-Ahead in Competitive
Online Convex Optimization,'' which was presented at ACM SIGMETRICS 2019
and published in ACM POMACS 2019, has a serious mistake, making the original
result invalid. 

<p>

Please see <a href="./corrigendum-pomacs19-error.pdf"> here </a> for an
explanation of the mistake.
We sincerefuly apologize for the mistake!

<p> 

We have produced a new result that may serve as a correction to the
above paper. See <a href="./infocom21-rla.pdf"> here. </a> Note that the
new result involves a new algorithm and a new competitive ratio, as well
as new analysis. This work will appear in IEEE INFOCOM 2021. 

<p> 

We sincerely thank Jianing Zhai and Prof. Minghua Chen for bringing the
mistake to our attention.