“ln(x)” is another way of writing log sub e of x https://en.m.wikipedia.org/wiki/Natural_logarithm

The “ln” of the “you son of a bitch. I’m ln” is referencing that identity

I agree, but I still have this idea that it’s rude to text people unless you have gotten permission first. I think it’s a relic from the 2000s-2010s when not everyone’s phone had texting and if you did text them they could get charged by their phone provider. Obviously nowadays that’s much less of a concern, but still feels like a social grey area for some reason