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Re:Palindrome Day 20200202 by susam on Saturday February 01, 2020 @10:39PM (#22214995)
The nice thing about today's date, 2020-02-02, is that it is palindrome in three date formats: YYYYMMDD, DDMMYYYY, and MMDDYYYY.

This should probably be called "Universal Palindrome Day" because it is a palindrome irrespective of the endianness (big, little, or middle) that is used in various countries.

Here is the list of all such dates until the year 9999:

  0101-10-10
  1010-01-01
  1111-11-11
  2020-02-02
  2121-12-12
  3030-03-03
  4040-04-04
  5050-05-05
  6060-06-06
  7070-07-07
  8080-08-08
  9090-09-09
The next such one is over 101 years away from now.

Here is my own blog post on this topic: https://susam.in/blog/universal-palindrome-day/ :-)

Re:Palindrome Day 20200202 by skrebbel on Sunday February 02, 2020 @12:42AM (#22215360)
I love the term "middle endianness" and how clearly it highlights how nuts the American date notation is.

EDIT: fwiw, in my native language, most numbers from 100 and 1000 are pronounced middle endian, so I'm not complaining.

Re:Palindrome Day 20200202 by Thorrez on Sunday February 02, 2020 @01:08AM (#22215449)
Little endian notation is somewhat mixed endian itself, because it contains 3 numbers, each number by itself is big endian, but the 3 numbers are arranged in little endian fashion amongst each other.
Re:Palindrome Day 20200202 by iso947 on Sunday February 02, 2020 @10:35AM (#22217341)
D/m/y is little endian. In a base 10,000 system there would be 3 symbols, each unique.
Re:Palindrome Day 20200202 by Thorrez on Sunday February 02, 2020 @04:15PM (#22219476)
Sure, but humans would have a hard time memorizing 10,000 symbols.
Re:Palindrome Day 20200202 by nkrisc on Monday February 03, 2020 @11:13AM (#22225466)
If each unique symbol for a number was made up of smaller symbols arranged using a simple algorithm you wouldn't necessarily need to memorize them all. Kind of like Roman numerals, but much a bit more complex.

I don't have to remember the exact symbol for 2,020 in Roman numerals, because I can figure it out. In fact, I have no idea what it would be without sitting down and doing so.

I'm not saying it would be a good system, but it could be usable by mere mortals. I guess you could debate if this would really be "10,000 unique symbols" or just something akin to our current writing system for numbers.

Re:Palindrome Day 20200202 by thaumasiotes on Sunday February 02, 2020 @12:59AM (#22215414)
The American date notation is simply a direct reflection of the spoken language. We say "February second, 2020" and we write "2/2/2020". (Contra the root comment, I can't agree that 2/2/2020 is a palindrome.) I don't see this as being crazy or even unusual.

When order matters, you invariably want big-endian notation, which is why that notation is acceptable everywhere regardless of the usual native notation. But by the same token, it means that all other styles are equally "nuts". European day-month-year notation doesn't have any technical advantages over month-day-year.

Re:Palindrome Day 20200202 by hibbelig on Sunday February 02, 2020 @03:41AM (#22215913)
That middle-endianness is spoken doesn’t make it better. It’s still crazy.

Starting with the most general and ending with the most specific is a logical order. Doing it the other way round is also logical. But starting with the middle makes no sense.

It doesn’t seem unusual to you because you use it often.

That said I’m German and I realize that German postal addresses are crazy for the same reason. I wish we‘d adopt the Chinese format: country first then province (state), then County then town then neighborhood then street and house.

German addresses are middle endian: street then house number then zip code then city then country. The right order seems to be: city, zip, street, house number. Most general to most specific.

Re:Palindrome Day 20200202 by mopsi on Sunday February 02, 2020 @04:03AM (#22215984)
What's so crazy about the German notation? Seems to make perfect sense, as it goes line-by-line from the smallest to the largest sorting unit:

1. Exact street location (street + house)

2. District (postal code)

3. City

4. Country

Also I prefer this order over the Chinese, because I assume most people handling mail will need to smallest details and it would just be very annoying if local mailmen had to skip over country and city names every time before reaching the bit they actually need.

Re:Palindrome Day 20200202 by hibbelig on Sunday February 02, 2020 @05:58AM (#22216362)
The house number is smaller than the street, but the street comes first. If we put the house number first, then we'd get a logical order.
Re:Palindrome Day 20200202 by Kaiyou on Sunday February 02, 2020 @02:42PM (#22218917)
You're thinking of street and house number as two things. Germans don't. Or at least I don't. Your approach makes as much sense as picking movie titles with numbers at the end apart into two things.
Re:Palindrome Day 20200202 by jgwil2 on Sunday February 02, 2020 @06:03PM (#22220084)
Street and house number are certainly two different things. It's more like series of movies (Die Hard 1, Die Hard 2, etc. are different movies but part of the same series. In the same way, a street could be seen as a series of houses or addresses. So the smallest unit is the house, then the street.
Re:Palindrome Day 20200202 by Kaiyou on Monday February 03, 2020 @04:39AM (#22222741)
Yes, it's like a movie series. It's Die Hard 2. That's one name, not two, "2" and "Die Hard", but one: "Die Hard 2".
Re:Palindrome Day 20200202 by jgwil2 on Monday February 03, 2020 @12:59PM (#22226905)
I didn't say it was two names, I said there are two different movies within the Die Hard series. Just like two different houses on the same street.
Re:Palindrome Day 20200202 by Kaiyou on Tuesday February 04, 2020 @05:38AM (#22234147)
Yes, but each movie is a single entity and the number is part of that entity. Just like with "street+house number". It's one entity, not two.
Re:Palindrome Day 20200202 by ddoeth on Sunday February 02, 2020 @04:42AM (#22216107)
I think he meant, that the street name is before the house number
Re:Palindrome Day 20200202 by lucideer on Sunday February 02, 2020 @04:47AM (#22216118)
You listed two details on one line to make the German notation seem non-crazy.

A more "logical" notation, as per the gp's comment would start:

1. Exact street location (house + street)

Re:Palindrome Day 20200202 by tikej on Sunday February 02, 2020 @07:14AM (#22216607)
In Poland We do it exactly as you said:

Street_name street_number/house_number

Postal_code, City, Country

Re:Palindrome Day 20200202 by Symbiote on Sunday February 02, 2020 @01:22PM (#22218399)
The typical English-influenced way to do it starts with the number,the most specific thing.

  10 Downing Street
  London
  SW1A 2AA
(The postcode is least-specific first: SW is South West London, 1 is the district nearest Central London, and the 2 would usually be a few streets and the AA 5-10 houses, but this is a unique code for an address that gets a lot of post.)
Re:Palindrome Day 20200202 by lucideer on Sunday February 02, 2020 @02:07PM (#22218679)
Funnily enough, with the addition of the newest element to that format — the postcode — to the end, this format also becomes less "logical", postcode being very specific.

Of course that's arguable, as postcode shouldn't really be considered a component of-, rather an alternative to- other sections of the address.

Re:Palindrome Day 20200202 by mrcarrot on Monday February 03, 2020 @07:19AM (#22223510)
A postcode (or local equivalent) isn't necessarily particularly specific. For example, here in Austria the equivalent of a postcode might cover a whole city district.
Re:Palindrome Day 20200202 by umanwizard on Monday February 03, 2020 @08:12AM (#22223812)
Yes, similar to the US. But British post codes (or at least the ones I’ve seen in London) are in fact very specific.
Re:Palindrome Day 20200202 by dajon on Monday February 03, 2020 @09:53AM (#22224589)
Indeed, a single postcode in the UK will contain (on average) about 20 addresses and (usually) only refer to a single street.
Re:Palindrome Day 20200202 by cfallin on Monday February 03, 2020 @10:51AM (#22225203)
ZIP+4 in the US is quite specific, though. E.g., my ZIP code is probably > 50k people but the ZIP+4 is just my apartment building.
Re:Palindrome Day 20200202 by yitchelle on Monday February 03, 2020 @05:28PM (#22230019)
You are missing the name of the house resident as the first line. Once I had my mail returned to the sender because my parents-in-law did not put our name on the envelope.
Re:Palindrome Day 20200202 by cortesoft on Sunday February 02, 2020 @03:55AM (#22215960)
For something like addresses, usage pattern is going to matter... if most mail is sent within the city, then putting street first makes sense, because the city is almost always the same; it shouldn't take up valuable real estate at the front of the address.

The broadest unit that is likely to change going first makes sense.

Re:Palindrome Day 20200202 by Wowfunhappy on Monday February 03, 2020 @11:15AM (#22225496)
> That middle-endianness is spoken doesn’t make it better. It’s still crazy.

The english language—and every other real-world spoken language—is full of rules and exceptions that make absolutely zero logical sense. How far down this road do you want to go?

As long as we speak in a specific order, I don't think it's crazy at all to write in that same order. After all, normal written sentences follow the spoken order of words, too.

Re:Palindrome Day 20200202 by bloak on Sunday February 02, 2020 @03:31PM (#22219231)
Hungarian addresses are (or were) worse. According to http://www.columbia.edu/~fdc/postal/, it's:

1. name of recipient, 2. town name, 3. street address or post box number, 4. four digit postal code.

(I have a vague memory of seeing that sort of order in German, too, in a historical context, but perhaps it was from Austria-Hungary.)

Re:Palindrome Day 20200202 by gsich on Sunday February 02, 2020 @03:56AM (#22215964)
Or from botton to top: country, city, zip, housenumber, street, name.
Re:Palindrome Day 20200202 by justinclift on Sunday February 02, 2020 @01:24AM (#22215489)
> We say "February second, 2020" ...

Interesting. We (Australian) say "Second of Feb, 2020". ;)

Re:Palindrome Day 20200202 by mcv on Sunday February 02, 2020 @03:54AM (#22215955)
In Dutch we say "2 februari 2020". So littleendian is perfectly natural for us.
Re:Palindrome Day 20200202 by Jare on Sunday February 02, 2020 @03:51AM (#22215951)
Spanish is "Dos de Febrero de 2020"
Re:Palindrome Day 20200202 by rags2riches on Sunday February 02, 2020 @02:11AM (#22215627)
What about the Fourth of July then?
Re:Palindrome Day 20200202 by Lio on Sunday February 02, 2020 @03:26AM (#22215868)
I don’t know, I always imagined that you said “4th of July” because up to that point you were Brits and that’s how we say it.

...and then the very next day, without adult supervision, you started saying your dates weirdly and dropping the “u”s out of words, stuff like that.*

* DISCLAIMER: May not be an accurate representation of history. :P

Re:Palindrome Day 20200202 by thaumasiotes on Sunday February 02, 2020 @05:14AM (#22216211)
It's more accurate than it might sound. If I recall correctly, the American spelling reforms were largely a one-man top-down effort driven by the ideological goal of being more separate from Britain.
Re:Palindrome Day 20200202 by justinclift on Sunday February 02, 2020 @06:32AM (#22216475)
It's commonly referred to as "Simplified English" for good reason. ;)
Re:Palindrome Day 20200202 by dcuthbertson on Sunday February 02, 2020 @11:13AM (#22217592)
> I always imagined that you said “4th of July” because up to that point you were Brits

True, but nowadays we say "Independence Day" :-)

Re:Palindrome Day 20200202 by iso947 on Monday February 03, 2020 @09:14AM (#22224249)
Re:Palindrome Day 20200202 by umanwizard on Sunday February 02, 2020 @09:39AM (#22217093)
You can say any date like that in American English, it’s just less common. “Today is the second of February” sounds perfectly natural, but I’d be more likely to say “Today is February second”.
Re:Palindrome Day 20200202 by loco5niner on Monday February 03, 2020 @12:28PM (#22226437)
As in everything else in American English, there are exceptions.
Re:Palindrome Day 20200202 by thaumasiotes on Sunday February 02, 2020 @02:52AM (#22215771)
What about it? It's the name of a holiday.

12/25 is often called Christmas, and yet 9/29 is never called Michaelmas. Same thing.

Re:Palindrome Day 20200202 by stevekemp on Sunday February 02, 2020 @10:57AM (#22217480)
The parent was making the point that generally Americans refer to dates such as "May 2nd", "April 14th".

But one of their biggest holidays is explicitly called "4th of July", changing the ordering.

Re:Palindrome Day 20200202 by thaumasiotes on Sunday February 02, 2020 @12:49PM (#22218177)
And a proper name is not good evidence of normal usage. "Christmas" is normal use in an older, Catholic method of identifying calendar dates. Americans don't use that method; most couldn't if they wanted to. But Christmas itself is still identified that way for historical reasons -- the word has gone from being an example of talking about the calendar to being an example of a proper name.

"4th of July" is not a method that Americans couldn't use if they wanted to, but it is an ossified usage that doesn't reflect how Americans generally refer to dates. Like Christmas, it is a proper name of limited evidentiary value.

Re:Palindrome Day 20200202 by Kaiyou on Sunday February 02, 2020 @02:46PM (#22218944)
Huh, where I'm from the 24th of December is Christmas. The 25th is the day after Christmas.
Re:Palindrome Day 20200202 by loco5niner on Monday February 03, 2020 @12:28PM (#22226448)
Really? Where are you from?

This might help explain how Santa delivers all those presents in "one night".

Re:Palindrome Day 20200202 by Kaiyou on Tuesday February 04, 2020 @05:37AM (#22234144)
Possibly it's the difference between being an atheist and a catholic, since I faintly remember my catholic friends receiving presents on the morning of the 25th, while I would receive them on the evening of the 24th.
Re:Palindrome Day 20200202 by thaumasiotes on Tuesday February 04, 2020 @11:41PM (#22244087)
Opening presents on Christmas Eve is a pretty common tradition.

Calling Christmas Eve "Christmas" is not common at all.

Re:Palindrome Day 20200202 by loco5niner on Tuesday February 04, 2020 @08:49PM (#22243265)
Interesting. Are you from Canada?
Re:Palindrome Day 20200202 by Kaiyou on Wednesday February 05, 2020 @05:37AM (#22245607)
I'm from Europe, but not from an English speaking country.
Re:Palindrome Day 20200202 by gmac on Sunday February 02, 2020 @03:59AM (#22215974)
Chicken and egg. I (in British English) say the second of February.
Re:Palindrome Day 20200202 by thaumasiotes on Sunday February 02, 2020 @04:40AM (#22216099)
I would agree that there's influence in both directions between the written pattern and the usual manner of speech. All I'm saying here is that there's nothing surprising about the written pattern matching the usual manner of speech. That is the primary purpose of writing; it's weirder for the writing not to match the speech. (Although certainly not unheard of; it is the norm in e.g. Chinese.)
Re:Palindrome Day 20200202 by elif on Sunday February 02, 2020 @05:00AM (#22216156)
Unfortunately, you're using an idiosyncratic American "usual manner of speech" to justify an idiosyncratic American format.
Re:Palindrome Day 20200202 by thaumasiotes on Sunday February 02, 2020 @05:12AM (#22216201)
And the problem with that is... what? Are you saying we should all speak Chinese because spoken Chinese dates go in correct sorting order?
Re:Palindrome Day 20200202 by umanwizard on Sunday February 02, 2020 @09:35AM (#22217073)
Idiosyncratic? Of course. People in different countries speak differently. Every natural language is totally arbitrary and “idiosyncratic”. What is your point?
Re:Palindrome Day 20200202 by iso947 on Sunday February 02, 2020 @10:42AM (#22217379)
The assertion that most people and most countries in spoken language say “day [of] month”, which I find anecdotally accurate, although that’s mainly in European countries and languages

This matches why almost every country in the world uses “d/m/y” in normal usage.

Re:Palindrome Day 20200202 by umanwizard on Sunday February 02, 2020 @10:52AM (#22217442)
If you were aware of the mind-boggling diversity of human language you would not make claims like “typical languages do X so one that doesn’t is idiosyncratic” (unless backed by serious research spanning the thousands of known languages). You would also not think experience with a few languages from the Indo-European family is generalizable.

Standard Chinese for example uses Y/M/D and I’m sure you can find many examples of other formats.

Re:Palindrome Day 20200202 by Symbiote on Sunday February 02, 2020 @02:40PM (#22218899)
I think the only major language using the M, D, Y spoken order are American-influenced English and Ewe (Ghana etc).

Several countries write a short data as M/D/Y, but these mostly have a significant American influence.

Re:Palindrome Day 20200202 by thaumasiotes on Monday February 03, 2020 @04:23AM (#22222663)
The claim was "almost every country in the world uses d/m/y in normal usage", which doesn't pass the laugh test.

It wasn't "almost every country in the world doesn't use m/d/y", even if you would have liked it to be.

Re:Palindrome Day 20200202 by iso947 on Monday February 03, 2020 @09:57AM (#22224646)
British English? Which part of the UK is that from.

I speak English English.

Re:Palindrome Day 20200202 by Naracion on Sunday February 02, 2020 @12:48PM (#22218172)
Out of curiosity, what's your native language?
Re:Palindrome Day 20200202 by skrebbel on Sunday February 02, 2020 @02:03PM (#22218636)
Dutch.

Afaik all Germanic languages except English¹ (and close relatives) have the same thing. Ie this stuff is the same in Dutch, German, Swedish, Danish², etc.

We don't say "Twenty-three" but "Three-and-twenty". So far so good, but we do the hundreds, thousands etc just like English does. Thus, 123 is pronounced "hundred-three-and-twenty", i.e. precisely as nuts as what Americans do with dates.

¹) I assume that English fixed this at some point along the way (maybe due to French influences?), because the special number names between 10 and 20 do follow continental Germanic rules, eg compare "sixteen" and "twenty-one". We mainland Europeans like to mock the English speaking world for their insane unit systems, but at least their numbers make sense.

²) Danish has it worse. They have the same insane number ordering plus insane number names.

3 is "tre", 30 is "tredive". 4 is "fire", 40 is "fyrre". So far so good. Like in many languages, 10x sounds a bit like x.

But 6 is "seks", and 60 is "treds" (!). To make matters worse, 5 is "fem" but 50 is.. "halvtreds" (!!). Similarly 9 is "ni" and 90 is "halvfems". In Danish, for x <= 5 < 10, 10x sounds like ["", "halv"][x mod 2] + ceil(x / 20). I tried mocking the language by saying "fems" instead of "hundrede" but I just got blank stares.

And I'm lucky enough to have grown up on the same insane middle endianness as the Danes. I can't imagine how impossible Danish numbers must be to learn for eg an English speaker. Every time my wife says a number in Danish I spend half a minute doing the math, "she said something with 'tre' in it, so threes, but it ended with an s, so three times twenty, oh but wait there was 'halv' in front of it so subtract 10, ah, fifty". But she didn't say that, she said "to-hundrede-tre-og-halvtreds". By the time I'm done with the math I already forgot the other digits :-)

Re:Palindrome Day 20200202 by Symbiote on Sunday February 02, 2020 @02:29PM (#22218815)
(And you didn't even mention how "tredive" is pronounced.)

Swedish and Norwegian (and English for that matter) used to count the Germanic way, but swapped to the modern way for 20 onwards at various points.

There's an English nursery rhyme "Four and Twenty Blackbirds" which has the old way as its title. English also used to use the vigesimal system. My great-grandfather was supposedly a bit of a traditionalist even amongst his rural friends, who poked fun at him for saying things like "two score nine? I'm not paying that!".

Re:Palindrome Day 20200202 by droithomme on Sunday February 02, 2020 @03:16PM (#22219144)
> how clearly it highlights how nuts the American date notation is

Middle Endian dates make sense when the season something happens in is important.

Re:Palindrome Day 20200202 by gorgoiler on Sunday February 02, 2020 @04:29AM (#22216062)
Just as with inches, feet, and pounds the system works better in practical real world conversation than it does in more formal language.

“When’s your birthday? 10/23. When are we going to Ma’s? 11/19 thru 11/29. When do you go back into therapy? 12/8.”

Re:Palindrome Day 20200202 by Symbiote on Sunday February 02, 2020 @06:26AM (#22216453)
“When’s your birthday? 23/10. When are we going to Mum’s? 19-29/11. When do you go back into therapy? 8/12.”

As it could be written in English in Britain, Australia etc.

23/10 is pronounced "23rd of October" or (usually) "23rd'f October" or "23rd'f the 10th".

The range is "19th to 29th of November" or "... of the 11th".

The pronunciation "second of the second twenty-twenty" is usually used when the listener is writing, typing or confirming the date in figures.

Re:Palindrome Day 20200202 by StavrosK on Sunday February 02, 2020 @07:22AM (#22216629)
It doesn't "work better" than any other system, you're just more used to it.
Re:Palindrome Day 20200202 by emanuensis on Sunday February 02, 2020 @10:02PM (#22221081)
i think this especially goes for the English system vs metric measurements (though confusingly the English do not use the Imperial system, officially at least) Our brains are much better wired for binary systems like bushels and pecks rather than the French derived decimal system which is only good for studious things (like science) where you have of many orders of magnitude to keep track of regularly. Much easier to communicate/grasp half than 5/10ths.

Similarly the Sexagesimal notation, in common use (clocks etc), points to an generalization that would have been much better than the French system, where we rely on primes for increasing places in the number. Eg 4321(primal) would be 4x5 + 3x3 + 2x2 +1x1 = 34(decimal). Historically we may be stuck with counting on our fingers and toes though, through eternity.

The more "logical" Metric system which is not an extension of the "practical" Imperial system is inevitably bastardized and Creoled in everyday usage. Eg one buys a "Pound Plus" of Chocolate from Trader Joe's (500 grams!). Why is the choice is not one (or fice) Hectogram(s) vs one Kilogram i do not know... except that Hectogram is so obtuse/abstruse i had to google it! Maybe someone in a Metric country can correct me, if they think i am wrong using words like abstruse. One inevitably finds doubling and halving in everyday commerce.

We would do a lot better to extend to tripling, quintupling etc, like the Babylonians did, than directly to the (insane, in my opinion :-) French 10x Metric system.

Not that i am an American chauvinist. Eg i think the American middle endianistic dating system is off the wall weird, and i go out of my way to circumvent it.

Re:Palindrome Day 20200202 by DonHopkins on Sunday February 02, 2020 @07:25AM (#22216637)
Does you native language also have gendered numbers? Is there gender parity with odd numbers male and even numbers female? Or does it enforce the numeric patriarchy by gendering prime numbers male and composite numbers female?

https://insight.kellogg.northwestern.edu/article/are_numbers...

https://www.livescience.com/15859-odd-numbers-male-female.ht...

Re:Palindrome Day 20200202 by ph2082 on Saturday February 01, 2020 @10:46PM (#22215023)
So it happened like 900 yrs ago and after next one it almost take 900 yrs for same date to happen. And I am alive on one of this rare event. Need to cut Cake. :)
Re:Palindrome Day 20200202 by felipemnoa on Saturday February 01, 2020 @10:55PM (#22215045)
Not to sound corny but if you really think about it every single day is rare, just in different ways.
Re:Palindrome Day 20200202 by susam on Saturday February 01, 2020 @11:02PM (#22215063)
Reminds me of the interesting number paradox[1]. This can be easily extended to dates too in this manner:

Every date is interesting. Proof by contradiction: If there exists a non-empty set of uninteresting dates, there would be an earliest date in this set. But the earliest such date is itself interesting because it is the earliest uninteresting date, thus producing a contradiction.

[1]: https://en.wikipedia.org/wiki/Interesting_number_paradox

Re:Palindrome Day 20200202 by Retric on Sunday February 02, 2020 @12:20AM (#22215291)
There is no largest or smallest real number. Therefore a set without a largest or smallest member is not necessarily empty.

Alternatively, being the smallest in the set of uninteresting numbers does not make a number interesting, at best it is unique like every other number and therefore uninteresting.

Re:Palindrome Day 20200202 by TylerE on Sunday February 02, 2020 @12:36AM (#22215341)
Not true of dates though, since you can set hard bounds at the big bang (or whatever) and the heat death of the universe.
Re:Palindrome Day 20200202 by marcosdumay on Sunday February 02, 2020 @10:49AM (#22217417)
You don't need both bounds anyway. A countable set without a lower bound in any representation is already a paradox.
Re:Palindrome Day 20200202 by _morgs_ on Sunday February 02, 2020 @02:17AM (#22215652)
So the universe creates time?
Re:Palindrome Day 20200202 by dkersten on Sunday February 02, 2020 @07:01AM (#22216561)
Yes. After the heat death, nothing will ever move or change and so it the universe will remain in a frozen state. Time will have stopped.

Sine time is relative based on the observer and observed, if neither change in any way (no “work” happened and no information is exchanged, even on the level of fundamental particles (or fields/loops/strings or whatever happens to be at the bottom)), for every possible combination of observer and observer, then time has not advanced in any meaningful sense.

Re:Palindrome Day 20200202 by fortran90 on Sunday February 02, 2020 @12:55AM (#22215403)
> There is no largest or smallest real number.

The interesting number paradox applies to natural numbers, not real numbers.

> Alternatively, being the smallest in the set of uninteresting numbers does not make a number interesting

You are taking this too seriously. :-) Everyone would agree that "interesting" is subjective. This is supposed to be a humorous paradox, not a mathematical fact!

Re:Palindrome Day 20200202 by Retric on Sunday February 02, 2020 @08:26AM (#22216807)
That was meant to be humorous, however dates are not natural numbers.
Re:Palindrome Day 20200202 by datanerd on Sunday February 02, 2020 @10:16AM (#22217257)
It is obvious that dates are not natural numbers. What is your point?

A set of dates obviously has an earliest date. The humour here is that an earliest date within the set of uninteresting dates is itself an interesting date by virtue of being the earliest such date in that set.

Re:Palindrome Day 20200202 by Retric on Sunday February 02, 2020 @11:03AM (#22217528)
> A set of dates obviously has an earliest date.

Uhh, no you’re thinking in terms of a finite set. From the set of all dates, what’s the latest possible date, or conversely the earliest possible date. The temptation is to say infinite BC is the earliest possible date, but infinity is not a number.

Re:Palindrome Day 20200202 by dragonwriter on Sunday February 02, 2020 @12:32PM (#22218076)
> infinity is not a number

Infinity is not a number, it's a set of numbers, but specific infinities (e.g., the cardinality of the natural numbers, aleph-naught) are individual numbers, just not finite numbers.

Re:Palindrome Day 20200202 by datanerd on Sunday February 02, 2020 @12:07PM (#22217922)
But there is no infinite BC, right? There cannot be any date earlier than the date of the big bang. That establishes a lower bound for the set of dates, does it not?
Re:Palindrome Day 20200202 by Retric on Sunday February 02, 2020 @12:53PM (#22218209)
The Big Bang is an apparent discontinuity, but we have no idea if a universe existed before this one. Alternatively, multiple universes could exist and those alternate universes could be much older. So at least theoretically things much older than our universe could exist.
Re:Palindrome Day 20200202 by mmhsieh on Saturday February 01, 2020 @11:50PM (#22215201)
there has got to be a better objective method to define interesting numbers other than inclusion in a number sequence compendium.

perhaps if we hypothesize that there are a (countably) infinite number of number theoretic theorems, might every number be either a unique case or the largest or the smallest example of some instance?

Re:Palindrome Day 20200202 by ph2082 on Sunday February 02, 2020 @03:36AM (#22215899)
Yes. I know. I Know. But you can't cut cake everyday. Need to make up some reason.
Re:Palindrome Day 20200202 by philshem on Sunday February 02, 2020 @03:39AM (#22215908)
From another comment on this thread

> 20300302, 20400402, etc

https://news.ycombinator.com/item?id=22214936

Re:Palindrome Day 20200202 by susam on Sunday February 02, 2020 @04:09AM (#22216004)
They are not universally palindromic.

For example, 2030-03-02 (yyyy-mm-dd) when written as 02-03-2030 (dd-mm-yyyy) is not a palindrome.

All dates in the list I have provided are universally palandromic, i.e., they are palindromes irrespective of the endianness (big, little, or middle) used to represent them.

Re:Palindrome Day 20200202 by mkagenius on Sunday February 02, 2020 @01:20AM (#22215479)
Also they contain only two distinct digits, rest mostly have 3 or more different digits.
Re:Palindrome Day 20200202 by toyg on Sunday February 02, 2020 @09:14AM (#22216991)
Yeah, we won’t get a two-digit universal palindrome for a long time (12-12-2121).
Re:Palindrome Day 20200202 by susam on Sunday February 02, 2020 @12:01PM (#22217895)
Yes, a YYYY-MM-DD format palindrome date that is also a palindrome in DD-MM-YYYY and MM-DD-YYYY formats cannot have more than two distinct digits.

Let us represent the 8 digits of such a date (in YYYY-MM-DD format) as abcd-ef-gh.

Since abcd-ef-gh (i.e., YYYY-MM-DD format) is a palindrome, we get a = h, b = g, c = f, and d = e.

Since ef-gh-abcd (i.e., MM-DD-YYYY format) is a palindrome, we get a = h, b = g, c = f, and d = e.

Since gh-ef-abcd (i.e., DD-MM-YYYY format) is a palindrome, we get a = f, b = e, c = h, and d = g.

Combining all of these, we get a = c = f = h and b = d = e = g.

Therefore, such a date must be of the format abab-ba-ba, i.e., it may have a maximum of only two distinct digits.

Re:Palindrome Day 20200202 by Aperocky on Sunday February 02, 2020 @09:55AM (#22217169)
Where is 2021-12-02 though?

edit: NVM. Should read better.

Re:Palindrome Day 20200202 by susam on Sunday February 02, 2020 @10:19AM (#22217272)
2021-12-02 (yyyy-mm-dd) is not a palindrome when written as 02-12-2021 (dd-mm-yyyy).

The list in my comment contains only those dates that are palindromes in all of these three formats: yyyy-mm-dd, dd-mm-yyyy, and mm-dd-yyyy.