Derek wrote:j is a non-real number whose square is +1. That's all there is to it. Don't try to relate it to anything you are already familiar with.
Yep (to you and gmalivuk, both), I'm not going to go and do a full Treatid on this issue, but that wiki page just really didn't (at first glance) give me the insight that I needed to understand the actual basis of the definition.
And that's with having been a vociferous arguer that there were
such things as "negative numbers", to my disbelieving peers, in primary school, and picking up on imaginary numbers well before I should. I've a feeling I need to go back to my Physical Systems notes on non-Euclidean representations and try to match those against the Minkowski stuff that we evidently didn't study at that area and level of undergrad studies.
(It might also affect my little project that simulates a stable finite unbounded (i.e. hyperspherical, inclusive of time) universe system in a sort of
Galilean geometry way. But that's a more playing about than serious, so it's only ever going to be as much a toy as the Asteroids universe geometry is.
Sorry to OP for butting in, though, I just was momentarily a bit too much bothered by it to let it pass without comment.