Deutsch Intern
Institute of Computer Science



Im Sommersemester 2019 findet auf Einladung von Prof. Dr. Alexander Wolff der folgende Vortrag statt:

Donnerstag, 26. September 2019, 11.30 Uhr, Seminarraum III, Informatikgebäude, Am Hubland


Prof. Dr. Riko Jacob
IT University of Copenhagen

Fragile Complexity of Comparison Based Algorithms



We initiate a study of algorithms with a focus on the computational complexity of individual elements, and introduce the fragile complexity of comparison-based algorithms as the maximal number of comparisons any individual element takes part in. We give a number of upper and lower bounds on the fragile complexity for fundamental problems, including Minimum, Selection, Sorting and Heap Construction. The results include both deterministic and randomized upper and lower bounds, and demonstrate a separation between the two settings for a number of problems. The depth of a comparator network is a straight-forward upper bound on the worst case fragile complexity of the corresponding fragile algorithm. We prove that fragile complexity is a different and strictly easier property than the depth of comparator networks, in the sense that for some problems a fragile complexity equal to the best network depth can be achieved with less total work and that with randomization, even a lower fragile complexity is possible.

(ESA 2019, Award for the Best Track-A Paper. Joint work with Peyman Afshani, Rolf Fagerberg, David Hammer, Irina Kostitsyna, Ulrich Meyer, Manuel Penschuck and Nodari Sitchinava.)