[singron]

It's covered in the article, but serialization just has to appear to execute in any sequential ordering of transactions. There are no other constraints about the ordering, so it technically allows the print to appear to run before the assignment.

Linearizability says that if A happens after B in real time (e.g. you don't start A until you get confirmation that B completed), A must see the effects of B. This would require the print to run after the assignment takes effect.