Talk:J-line

Untitled

I've tried to add a bit to the article -- it wasn't so clear to me what the relation to congruence subgroups was meant to be, or what $M(\cdots )$ was meant to represent -- unfortunately the cited reference is several hundred pages! So I've left this alone for now, but it should be clarified.

Dzackgarza (talk) 19:58, 22 March 2022 (UTC)