A parallel algorithm for maximal independent set (MIS) in hypergraphs has been a longstanding algorithmic challenge, dating back nearly 30 years to a survey of Karp & Ramachandran (1990). The best randomized parallel algorithm for hypergraphs of fixed rank r was developed by Beame & Luby (1990) and Kelsen (1992), running in time roughly (log n) r! .We improve the randomized algorithm of Kelsen, reducing the runtime to roughly (log n) 2 r and simplifying the analysis through the use of more-modern concentration inequalities. We also give a method for derandomizing concentration bounds for low-degree polynomials, which are the key technical tool used to analyze that algorithm. This leads to a deterministic PRAM algorithm also running in (log n) 2 r+3 time and poly(m, n) processors. This is the first deterministic algorithm with sub-polynomial runtime for hypergraphs of rank r > 3.Our analysis can also apply when r is slowly growing; using this in conjunction with a strategy of Bercea et al. (2015) gives a deterministic MIS algorithm running in time exp (O( log(mn) log log(mn) )). This is an extended version of a paper appearing in the ACM-SIAM Symposium on Discrete Algorithms (SODA) 2018. 0 In [10], Kelsen discussed one straightforward approach to derandomize the randomized algorithm by drawing the random bits from a probability space with k-wise independence. When k is constant, this space has polynomial size, and so can be searched efficiently. However, this leads to relatively weak concentration bounds, and so the resulting algorithm runs in n ǫ time and poly(n) processors for any constant r and ǫ > 0. When k ≥ Ω( log n log log n ), the algorithm runs in polylog(n) time, but requires super-polynomial processor count.The probabilistic methods underpinning polynomial concentration bounds are similar to those for sums of independent random variables. There have been numerous powerful techniques developed for the latter, much more powerful than k-wise-independence for constant k. Unfortunately, there are severe technical roadblocks to applying these to non-linear polynomials. To the best of our knowledge, polynomial concentration bounds have not led to any efficient deterministic algorithms.
Our contributionsIn Section 2, we give a slightly modified form of Kelsen's randomized algorithm, and show an improved bound on its running time.Theorem 1.1. There is a randomized parallel algorithm, running in (log n) 2 r+3 +O(1) expected time and O(n + m log n) processors, to produce an MIS of a rank-r hypergraph.There are two main ingredients to this improvement. First, we use a concentration inequality due to Schudy & Sviridenko [16], which is much tighter than the bounds originally developed by Kelsen. Second, we use an alternate degree statistic to measure the algorithm's progress. This measure is defined in terms of a single scalar value, which is used globally to bound the degrees throughout the graph. In addition to better running time, this substantially simplifies the analysis of [2, 3, 10], which used multiple, int...