qsortnilnilqsort.xy++qsortlowersxy.xqsortgreatersxylowersxnilnillowersx.yzif<=yx.ylowersxzlowersxzgreatersxnilnilgreatersx.yzif<=yxgreatersxz.ygreatersxz2.110qsort.xyqsortlowersxyqsort.xylowersxyqsort.xyqsortgreatersxyqsort.xygreatersxylowersx.yzlowersxzgreatersx.yzgreatersxztrueqsort.xyqsortlowersxyfalseqsort.xyqsortgreatersxyfalseqsort.xylowersxyfalseqsort.xygreatersxyfalselowersx.yzlowersxztruelowersx.yzlowersxz1false12true2greatersx.yzgreatersxztruegreatersx.yzgreatersxz1false12true2AProVEAProVE Commit ID: 794c25de1cacf0d048858bcd21c9a779e1221865 marcel 20200619 unpublished dirty Statistics for single proof: 100.00 % (9 real / 0 unknown / 0 assumptions / 9 total proof steps)http://aprove.informatik.rwth-aachen.deJohnDoe