Readit NewsKings have Chebysev geometry while Rooks have taxicab geometry: https://en.wikipedia.org/wiki/Taxicab_geometry#See_also
It's left as an exercise for the reader to figure out the geometry of the remaining pieces.
Well, the point is to scan all messages, period.
And then to detect those that come from predators, not adults. How often do parents convince their children to send... revealing pictures? Or to meet them somewhere? How often do parents introduce themselves to their children in messages?
You can't seriously believe that a conversation between parents and children always looks like a conversation between a predator and children, can you?
No, we don't.
When we refer to 'the first year of life', we mean the time from birth until you turn 1.
Similarly, you'd say something like 'you're a child in the first decade of your life and slowly start to mature into a young adult by the end of the second decade', referring to 0-9 and 10-19, respectively.
First = 0 Second = 1 Toward = 2 Third = 3 …
This way, the semantic meaning of the words “first” (prior to all others) and “second” (prior to all but one) are preserved, but we get sensical indexing as well.
nanoacre = about 4 square millimeters
microfortnight = about 1.2 seconds
beard-second = 5-10 nanometers (depending on who you ask), or the length an average beard grows in one second
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this is....more popular than i expected. the server's gonna be having some problems for a while
(Maybe I am too dogmatic)
Incidentally, I find it amusing that in Europe, the ground floor is zero, while in the US, it's one. (A friend of mine arrived at college in the US and was told that her room was on the first floor. She asked whether there was a lift as her suitcase was quite heavy...)
As a mathematician, yes, I do. Pretty much everything becomes simpler if you treat zero as the first natural number.
> Incidentally, I find it amusing that in Europe, the ground floor is zero, while in the US, it's one.
I really think it makes no sense to number the ground floor as 1. This means if you want to know the height of the nth floor, you have to multiply the height of a story by (n-1).
There are a ton of other cases where you have to needlessly subtract 1 when people use 1-based indexing. To name a few
- Dates: why did the 21st century start on 1/1/2001? Why are the 1800s the 19th century? It doesn’t make any sense. If we indexed from zero, today would be 5/0/2023 (5 months, 0 days, 2023 years since the common era), in the 20th century. It all becomes so easy and intuitive. - Mathematical foundations: If we are using set theory to encode mathematics, how is the number 1 defined? As a set containing itself? This leads to paradoxes in many cases. As the set containing a different single element? Then we can call its contents 0. - Musical intervals: why do two thirds (ok, major and minor, but I’ll gloss over that) make a fifth? Does 3+3=5? The fact that musical intervals index from 1 significantly increases the cognitive burden for music theory. It becomes much easier when we index from 0. - Birthdays: Age is correctly indexed from zero, but it may seem counterintuitive that your first birthday is the day you are born. So when is your second birthday? The day you turn 1, of course. The word “third” sounds like 3, so it seems reasonable to me to introduce a new ordinal here (I like “toward”). - Computing: languages that use 1-based indexing are obscuring what is actually going on; they generally just subtract 1 internally from the user’s input. They have to, since indexing from 0 is fundamentally more efficient at the hardware level. 4 bits can only store 15 possible addresses if you throw away 0.
These are just a few examples and by no means an exhaustive list. Conversely, I have yet to know of a single instance where 1-based indexing makes more sense or simplifies things (aside from being more compatible with legacy features of our society).
After a while, when you think deeply about it, you start to feel that 0-based indexing is something closer to a fundamental truth, rather than simply a convention. Indeed, I propose that the only reason people find 0-based indexing counterintuitive is due to social conditioning.
As far as I've seen, the group law is what makes elliptic curves special. Are they the _only_ flavour of curve that has a nice geometric group law? (let's say aside from really simple cases like lines through the origin, where you can just port over the additive group from R)
Of course, the homeomorphism to (R/Z)^2 does not respect the geometry (it is not conformal). If we want the map to preserve angles, we need our fundamental domain to be a parallelogram instead of a rigid square. The shape of the parallelogram depends on the coefficients of the cubic, and the isomorphism is uniquely defined up to choice of a base point O (mapping to the identity element; for elliptic curves, this is normally taken to be the point at infinity). You still get a group law on the parallelogram from vector addition in the same way, and this pulls back to the precise group action on the elliptic curve.
The real magic is that the resulting group law is algebraic, meaning that a*b can be written as an algebraic function of a and b. This means you can do the same arithmetic over any field, not just the complex numbers, and still get a group action.