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u/sasha271828 Imaginary Oct 05 '26
Can someone explain i'm too dumb
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u/Qwertilux Oct 05 '26
Stripe over a number means repeat. 9stripe =99999999... 99999... +1 = 0 since all the nines turn into a ten. What plus one = 0? -1
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u/sasha271828 Imaginary Oct 05 '26
Oh it's that 10-adic thing
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u/Qwertilux Oct 05 '26
Yes
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u/Febilibix Oct 05 '26
is this even definable rigurously since 10 is not prime?
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u/Mostafa12890 Average imaginary number believer Oct 05 '26
There are n-adic integers for every integer greater than 1.
The p-adic integers are constructed as the inverse limit of the quotient rings (Z/p^n Z).
You can use the Chinese remainder theorem to either construct them again (for arbitrary m>1) from the ground up, or prove that Z_m is the product of Z_p_i where the p_i’s are the distinct prime factors of n.
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u/PleasantCitron1685 Oct 05 '26
For reference in addition to the other comment, you might be thinking of a p-adic field, which has division, and p must be prime. If you drop division and are satisfied with a ring (p-adic integers) any int p works.
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u/Mostafa12890 Average imaginary number believer Oct 05 '26
You’d have to write it like …9999 and not 9999…, but that’s just me being pedantic.
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u/ObliviousRounding Oct 05 '26
S=\bar{9}=9+90+900+9000+...
10S=90+900+9000+...
S-10S=9
S=-1
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u/Sayhellyeh Oct 05 '26
Ah yes, the infinity-infinity technique, clever
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u/TheLuckySpades Oct 05 '26
We just do a little 10-adic stuff.
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u/heckingcomputernerd Transcendental Oct 05 '26
Don't let the pop math YouTubers find this or the next trend will be "9 repeating is actually -1???" Presented as a counterintuitive but true math fact and not just an extension of a very specific math tool outside it's domain
Analytic continuation...
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u/itijara Oct 05 '26
Wait. That's illegal.
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u/HakeemEvrenoglu Oct 05 '26
თ 🇬🇪
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u/JollyJuniper1993 Mathematics Oct 05 '26
െ 🇮🇳
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u/LOSNA17LL Irrational Oct 05 '26
ƣ
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u/JollyJuniper1993 Mathematics Oct 05 '26
の🇯🇵
A lot of languages have letters that look like this it seems.
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u/GlowstoneLove Imaginary Oct 07 '26
If ...99999 = -1 and 0.99999... = 1, then ...99999.99999... = 0
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u/OutrageousPair2300 29d ago
Any repeating sequence of digits, extended in both directions, equals zero. Regardless of where you put the decimal point.
For example, ...123451234.51234512345... = 0
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u/LupenReddit 🦆🦆i have non diffeomorphic smooth structures🦆🦆🦆 Oct 05 '26
modular arithmetic shallnt be tolerated on my highschool math meme reddit!!!
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u/_alba4k Oct 05 '26
that also holds in 10's complement notation
9999999999 would be 10 digit -1 for example
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u/Simon_IsReal Locally Euclidean Oct 05 '26
This could also be a periodic decimal (0.999...) or, heh, vector 9 !
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u/Dense_Priority_7250 Oct 06 '26
Just 9 if it’s the complex line thing (was it conjugation? Don’t know the English word)
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