RuleML+RR-companion 2021: International Rule Challenge, Industry Track, and Doctoral Consortium 2021
: proceedings of the 15th International Rule Challenge, 7th Industry Track, and 5th Doctoral Consortium @ RuleML+RR 2021, co-located with 17th Reasoning Web Summer School (RW 2021) and 13th DecisionCAMP 2021 as part of Declarative AI 2021 : Leuven, Belgium (virtual due to Covid-19 pandemic), 8-15 September, 2021