1. Department of Mathematics Education, and Institute of Pure and Applied Mathematics Jeonbuk National University Baekje‐daero Deokjin‐gu Jeonju‐si South Korea
2. Department of Mathematics Yonsei University Yonsei‐ro Seodaemun‐gu Seoul South Korea
3. Research Institute for Mathematical Sciences, RIMS Kyoto University Kyoto Japan
4. Department of Mathematics Chungnam National University Daehak‐ro Yuseong‐gu Daejeon South Korea