There I found a link to MathOverflow post.
I visited there, and I came up with some questions about an answer (of Sankyu Kim), because the OP said some statements with doubt that his answer might be incorrect. Also I tried to find Euler- chi function which was mentioned in his answer on google, but I could only find Euler-legandre function, etc.
I checked ChinaHonkong(OP)'s recent activity and Sankyu's recent activity and found out that they haven't been active for years.
Obviously they seem not to reply to my comments.
What should I do? May I ask a new question about someone else's post?
If you want me to post the questions not on MO but Math SE please recommend me.