Ciro Santilli @cirosantilli 37

You need separate accounts for different countries: money.stackexchange.com/questions/73361/two-banks-in-two-countries-is-it-possible-to-have-a-unique-paypal-account it's a pain.

This idealization does not seems to be possible at all in the context of Maxwell's equations with pointlike particles.

No open signup it seems. TODO CV of owner.

They are making a proof assistant to integrate into the website: github.com/bookofproofs/fpl/, reminds Ciro Santilli of website front-end for a mathematical formal proof system.

Convergence: math.stackexchange.com/questions/629630/simple-proof-euler-mascheroni-gamma-constant

Same value if you swap any input arguments.

The bioinformatics database: www.ncbi.nlm.nih.gov/

Here's a good example of what you can get out of it: E. Coli K-12 MG1655

Related: en.wikipedia.org/wiki/Protein_(nutrient)

In plain English: the space has no visible holes. If you start walking less and less on each step, you always converge to something that also falls in the space.

One notable example where completeness matters: Lebesgue integral of $L^p$ is complete but Riemann isn't.