SizeandConnectedness updated file post Hlevel -> Truncation

[IanRay11]

Just want to log my progress so far. Much more to do.

[IanRay11]

@tomdjong I've finally finished the formalization of Dan's paper. I need to do some cleaning up and typo checking... Also you will likely wish for me to split into multiple PRs since there are multiple file changes (although ever change was directly motivated by something needed for Dan's paper.) Let me know.

[tomdjong]

Thanks @IanRay11! Could you:

1. Split this into two separate PRs: one for the new file and one for everything else (this one should come first).
2. Give a proper citation to Dan's paper, including the title, year, journal, and its DOI.
3. Check for unused imports.
4. Open a PR after you've cleaned up and commented where necessary.

Thank you!
(I will also close this PR.)

[IanRay11]

On it!