MathNet.Numerics has a pretty solid linear systems solver, and has multiple additional native providers that, depending on what hardware you have to work with, and the size of your solves, dramatically increases performance.

You could… but it’s singly not setup for that. There are blog softwares out there that support activitypub-- I have no experience with it, but microblog.pub was nativity designed as an activitypub blog. There’s also a WordPress plugin that’s basically official (maintained by the company that owns WordPress.com) and has known good integration to at least mastodon, so I would assume it works well with lemmy, peertube, etc, since AFAICT, mastodon is the most opinionated of them when it comes to activitypub conformance.