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> which I have swutch to

That's a past participle I've never seent before

Second guessed myself and had to look up whether this was actually a word

If it was phrased 'to which I have swutch' I don't think I'd bat an eyelid!

(i.e. past perfect, I think?)

If 'swutch' is the (past) participle of 'to switch':

Perfect: "to which I have swutch"

Pluperfect/past perfect: "to which I had swutch"

Oh yes, thanks.

Let's go crazy and do: to whuch I have swutch.

Google says the correct term is, in fact, Nintendo Switch.

I assume it lets you know where to buy one as well.

How’d you guess?

Trust Google with the facts.

I find this all much ado ablaut nothing.

maybe you haven't liveth long enough

For some reason part participles are particularly hard for me too (native English speaker who speaks no other languages fluently). (they must just be a mess in English? I can't imagine how non-native speakers ever get any of them)

I'm going to go with swutcheted

English verbs are pretty tame compared to Slavic verbs that can be modified with all kinds of perfective prefixes.

On the other hand, Chinese verbs are even easier. They don't even have a tense!

I wouldn’t say that Chinese verbs have no tense so much as that they are uninflected and that tense is marked with particles (which admittedly do not cause difficulties with irregular infexions).

Chinese technically does not have grammar tenses, but it has aspects indicated by particles. They mark the completion status, direction, presence, and so on.

However, the verbs themselves don't have tense. So these sentences can be identical: "I will walk home, then I will eat a cake" and "I walked home, then I ate a cake".

The overall timeframe can be given by a larger context: "Once my shift is over, I ..." / "I drank too much yesterday, that's all I remember: ".

It's simply not possible in English because every verb has a grammar tense built into it.

For entertainment look up Germanic string and weak verbs.

autocorrect unspelling above: string -> strong

( https://en.wikipedia.org/wiki/Germanic_strong_verb )

Like the joke of the guy returning to Boston after being away for years; asks his cab driver "Do you know where I can get scrod" and the driver says "Sure, but I've never heard that in the past perfect before!"

This might be the first time I get a joke's punchline but not the setup

Scrod is the name for a small whitefish; he was looking for a seafood restaurant.

You can create infinite such jokes that end with:

…and the duck said to the bartender, “put it on my bill”

Hmmm. When I heard that joke long ago, the driver said it was the pluperfect subjunctive. And here I took his word for it.

Same thing. From Wikipedia: "The pluperfect (shortening of plusquamperfect), usually called past perfect in English"

Another especially funny part of that joke for me is that this is set in Boston (which has a couple of important colleges) ... because someone once told me that a lot of post-graduates of that college I was attending were driving taxicabs in that city.

"swutch"

Compilation error at line 173.

I assume by

  144 : Jan, Feb, Mar
  025 : Apr, May, Jun
  036 : Jul, Aug, Sep
  146 : Oct, Nov, Dec

You mean: Jan = 1, Feb = 4, Mar = 4, etc.

Yeah, since they’re all mod 7.

Exactly so.

I remember them in this table because they are squares (except for December), as well as "highlights" ... May=2 and August=3 are two that I have "to hand".

This was the first explanation that I immediately memorised. Thank you for sharing. I got quite a few right, but as I experimented I failed on February 7th 2032. My math was:

    Years since 2012 is 20
    Leap years is 20/4 = 5
    Magic month number = 4
    Date is 7
    (20 + 5 + 4 + 7) % 7 = 1

So I was expecting Sunday, but the answer is Saturday. After some thought I realised: 2032 is a leap year and the chosen date is before February 29th. In those cases (on or before that day), it is necessary to subtract 1.

Exactly so ...

> Leap years is 20/4 = 5

... but because you are in February you have not yet had that leap year, so it's only 4, and then the sums work.

> A "magic number" for each month. There are mnemonics, and they can be computed from first principles if needed. It's also easy to remember a few and then compute the others.

  > 144 : Jan, Feb, Mar
    025 : Apr, May, Jun
    036 : Jul, Aug, Sep
    146 : Oct, Nov, Dec

It can be useful to combine mnemonics and computation. Consider this sequence:

  0, 1, -1, 0, 0, 1, 1, 2, 3, 3, 4, 4

It is the offset between the day of the year of the 1st of each month and the day of the year the 1st would be if the preceding months had all been 30 day months. For example if the first 11 months had all been 30 day months Christmas, December 25, would be day 30 x 11 + 25 = 355. Add the 12th item from the offset sequence, 4, to that to get the real day of the year for December 25th, which is 359.

The offset sequence is fairly easy to memorize.

Once you have that sequence memorized its easy to get the month magic numbers for day of week calculations. There are a few different sets of month magic numbers in use, but for all of them:

  Magic(n) = 2 n + Offset(n) + c

where Magic(n) is the magic number for month n (1 ≤ n ≤ 12), Offset(n) is the n'th item in the offset sequence, and c is a constant that depends on just what set of magic month numbers you use. For the 1 4 4 0 2 5 0 3 6 1 4 6 magic numbers c = -1.

For example for month 12, December, we get 2 x 12 + 4 + -1 = 6 mod 7.

By memorizing the offset sequence and using that to get the month magic numbers you get, at the cost a small amount of calculation to get the month numbers, easy day of year and days between dates calculations.

Of course it works both ways. Given memorized month magic numbers you can compute Magic(n) - 2 n - c and that will equal Offset(n) mod 7. As long as you remember that Offset(n) is in [-1,4] and so adjust anything outside that range by adding/subtracting multiples of 7 to get into range it should be fine.

I am struggling to understand the advantages over the Lewis Carroll method, which I find very simple and quick. It seems to add quite a lot of complexity.

Really? Colin's method seems pretty simple to memorize and work with. Especially since it's all addition mod 7. Given that the mod operator distributes over addition you can work answers out easily while working with small numbers.

For example, what day of week was September 2, 1945?

    45/4 = 11 (mod 7 = 4)
    45 mod 7 = 3 (easy to work out from 7 times table)
    September = 6
    2

So you've got 4 + 3 (disappears under mod 7) and 6 + 2 mod 7 = 1. So, the second world war ended on a Sunday.

I'm struggling to see why you think this is more complex ... the methods seem completely equivalent to me. The Carroll method does:

1: A calculation for the Century-Item ... divide by 4, take overplus from 3, multiply remainder by 2.

2: A calculation for the Year-Item ... Add together the number of dozens, the overplus, and the number of 4’s in the overplus.

3: A calculation for the Month-Item ... alternatively, memorise a table: the required final numbers after division by 7 are January, 0; February, 3; March, 3; April, 6; May, 1; June, 4; July, 6; August 2; September, 5; October, 0; November, 3; and December, 5.

Note that these numbers are exactly those in my table, minus 1.

4: Include the Day-Item.

Then add them all (mod 7) and convert the number to a month.

It's exactly equivalent to what I described, except the Carroll method has additional calculations for the year.

Possibly it was in the clarity of his explanation. That makes sense, thank you.

I think it's unreasonable for you to have been downvoted, and I've given you an upvote to do what I can to balance that. Expressing confusion over something like this is perfectly reasonable.

> Then Sunday=1, Wednesday=4, etc.

That's a helpful encoding because it matches up with numbering that's routinely used in Portuguese, Hebrew, Greek, and by Quakers, among many others.

https://en.wikipedia.org/wiki/Names_of_the_days_of_the_week#...

These are mostly ultimately because of the Hebrew Bible account in which Sunday is the first day of creation (e.g. Genesis 1:5, 1:8, 1:13, ...).

The numbering itself has little or nothing to do with the Bible. The practice of numbering days of the week is, as the page you linked suggests earlier, widespread and much older than the Bible.

Sunday is the day of creation in the Bible because it was the first day in the calendar being used where Genesis was written and translated, so "Day 1" became "Sunday" because to the translator "Sunday" was the first day. That calendar itself was not mathematical - the Hebrew calendar was an empirical lunisolar calendar with arbitrary intercalarion for thousands of years until it was fixed in 2CE in Judea, and it took another thousand years for this practice to become consensus, so Sunday being the day of creation is purely incidental and not a necessary intersection.

Ascribing the Bible into it is gratuitous and useless. While it might be a reason why a small proportion Christians use it, it only explains a tiny minority of its usage, not most of it. It's just explained by it being an obvious way to name days.

He didn't ascribe the Biblical narrative to the convention, he mentioned that they match. They could match due to coincidence, due to having a common ancestor, or due to the Biblical narrative itself following the extent (as you claim) standard.

I wrote "mostly ultimately because of", so I did mean to say that I thought the Biblical narrative was the historical reason that most cultures and languages that use this numbering did so.

I'm pretty curious about this question, which I've previously asked in the form of "for how long has there been a worldwide consensus about which day of the week it is?". One answer that I heard is sort of akin to sudosysgen's account, in that some people suggested that the question might not be meaningful: there may have been different cultures with a seven-day week and, when they made sustained contact, instead of debating with each other about "which day of the week it is", they may have understood themselves to be translating their existing names for the weekdays -- some of which were based on numbers.

To the extent that that's a good way of talking about it, I also don't have a good understanding of when those translations would have happened, or who would have made them.

It most likely comes from Greek, as the first time the Bible would be translated in a language where days had names. Some Greek calendars used the seven day week which seems to originate from the Sumerians, and naturally the day of the Sun would be the choice for the first day in the Greek pantheon.

I just looked in the Septuagint and (I guess unsurprisingly) it uses ἡμέρα μία, ἡμέρα δευτέρα, ἡμέρα τρίτη. So it wasn't literally directly in the translation process. One could also say that the Genesis text is counting days rather than naming them, as Genesis 1:5 for says יוֹם אֶחָד ('one day') whereas the "name" of the day in Hebrew is יוֹם רִאשׁוֹן ('first day').

This author argues that the "the Jewish, biblical week and the planetary week of astrological origin" were combined in Rome rather than Greece, while agreeing that there are earlier antecedents for the use of the seven-day week.

https://blogs.fu-berlin.de/zodiacblog/2022/05/02/the-origins...

Wikipedia on "nundinae" seems to roughly agree with this interpretation:

> The 7-day week first came into use in Italy during the early imperial period. For a time, both systems were used together, but the nundinae are seldom mentioned in extant sources after the Julio-Claudian period. The nundinal cycle had probably fallen out of use by the time Constantine adopted the Hebrew weeks for official use in AD 321, altering the day of rest by declaring the Lord's day the Day of the Sun (dies Solis) a legal holiday. Different scholars have placed the end of 8-day markets at various dates from the late 1st to early 5th centuries.

A little pressed with time, but does it handle leap years properly? Since every year divisible by 100 is not a leap year, unless it is also divisible by 400?

(E.g. 1900 is not a leap year but 2000 is)

There is a small correction needed for January and February in leap years, and I haven't included the corrections for pre-1900. The Carroll method does deal with these issues and I have internalised them, but I find I never use them, so I retain only the simpler version.

One simple way to do January and February is to treat them as part of the previous year (with an adjustment for the constant you remember for those months).

I don't quite understand. Your magic month numbers are 3 digits, but you only use one digit in your example. And how does substituting 2012 work, when 2012 was a leap year but 1900 wasn't?

> 144 : Jan, Feb, Mar

So Jan=1, Feb=4, Mar=4

> 025 : Apr, May, Jun

So Apr=0, May=2, Jun=5

... and so on.

And we can substitute 2012 for 1900 because we make a correction in Jan and Feb in leap years. Knowing that 1900 was not a leap year means we don't make the correction, but 2012 was a leap year so we do.

Thanks. Would have been easier to grasp though if you'd phrased it like

> 1,4,4 : Jan, Feb, Mar.

I learned this at MathCamp from Conway himself! The mnemonics he taught us for the “doomsdays” were:

> Even months aside from February, same date as the month, so 4/4, 6/6, 8/8, 10/10, 12/12.

> “Working 9 to 5 at 7-11”: 5/9, 7/11, 9/5, 11/7

> Jan–Mar are a bit arbitrary: Feb is the last day of the month (so 2/28 or 2/29), March is the 0th day (same), and Jan is 1/31 or 1/“32” depending on if it’s a leap year.

Why is it called "doomsday"? Neither the wiki article nor MW dictionary definition explain this etnymology/usage.

https://www.merriam-webster.com/dictionary/doomsday

"When I taught at Princeton five years ago, I asked my old college roommate to get to John Conway and ask. To my surprise it took 3, not 2, degrees of separation to get to him. He said he wanted the name to end in "-day" and "Dooms" popped into his head."

-- https://www.rudy.ca/doomsday.html

Likely that sprung to mind because of the "Domesday Book":

"Domesday Book (/ˈduːmzdeɪ/ DOOMZ-day; the Middle English spelling of "Doomsday Book") is a manuscript record of the Great Survey of much of England and parts of Wales completed in 1086 at the behest of King William the Conqueror."

-- https://en.wikipedia.org/wiki/Domesday_Book

> partly because once you have the skill you find it's surprisingly useful.

A statement I find to be true in general.

You don't have to take the mod 7 of each of the values. You can sum them into one number and take its mod 7. You'll get the same result.

You can take mod 7 anywhere you like as you go. It's a tool to make the arithmetic easier.

No, you don't need to do it relentlessly as you go, but it can be used in an ad hoc manner to keep the numbers small.

Having said that, if you have 24, you can reduce it (mod 7) to 10, which you might find it easier to work with rather than reducing it to 3. Similarly if you start with 27 you can reduce it to -1 (mod 7). You don't always need to reduce things to the range [0..7).

(Note, by convention the square bracket implies "included" and the round bracket implies "excluded", so [0..7) is the collection {0,1,2,3,4,5,6}.)

Judging by that table (month numbers being the same for Feb + March in 2024), you have to adjust -1 for dates before March in leap years?

Yup. The designers of these kind of day of the week systems generally design as if the year started on March 1, so leap year shenanigans just mess with the last day of the year. They take that into account in their formulas for the century-based and year-based terms of the formulas so that each March 1 will be the right number of days after the previous March 1.

That way when using the system you don't have to care about leap years except during January and February. The formulas always give February 28th as the day before March 1 which in leap years is one day too late because of February 29th, and so as you surmised you need to adjust by -1 for dates in those months.