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تسجيل مستخدم جديدOnline Geometric Discrepancy for Stochastic Arrivals with Applications to Envy Minimization
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Consider a unit interval $[0,1]$ in which $n$ points arrive one-by-one independently and uniformly at random. On arrival of a point, the problem is to immediately and irrevocably color it in ${+1,-1}$ while ensuring that every interval $[a,b] subseteq [0,1]$ is nearly-balanced. We define emph{discrepancy} as the largest imbalance of any interval during the entire process. If all the arriving points were known upfront then we can color them alternately to achieve a discrepancy of $1$. What is the minimum possible expected discrepancy when we color the points online? We show that the discrepancy of the above problem is sub-polynomial in $n$ and that no algorithm can achieve a constant discrepancy. This is a substantial improvement over the trivial random coloring that only gets an $widetilde{O}(sqrt n)$ discrepancy. We then obtain similar results for a natural generalization of this problem to $2$-dimensions where the points arrive uniformly at random in a unit square. This generalization allows us to improve recent results of Benade et al.cite{BenadeKPP-EC18} for the online envy minimization problem when the arrivals are stochastic.
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