just invented perpetual motion
27.01.2026 21:33 β π 1 π 0 π¬ 0 π 0@almostsure.bsky.social
George Lowther. Author of Almost Sure blog on maths, probability and stochastic calculus https://almostsuremath.com Also on YouTube: https://www.youtube.com/@almostsure
just invented perpetual motion
27.01.2026 21:33 β π 1 π 0 π¬ 0 π 0I remember doing this stuff before. The coupon collectors problem. Could compute exactly and approximate, or approximate using a Poisson process from the start.
27.01.2026 14:50 β π 0 π 0 π¬ 1 π 0something something Gumbel something
27.01.2026 14:45 β π 0 π 0 π¬ 1 π 0Youβre probably familiar with Fourier transforms. But, did you know that it can be viewed as a 90Β° rotation in the time-frequency domain and we can rotate by any angle via fractional Fourier transform.
Explains why applying FT twice gives reflection (rotation by 180Β°).
The Producers by Mel Brooks
22.01.2026 12:46 β π 7 π 0 π¬ 0 π 0Inaugural Board of Peace meeting is under way
22.01.2026 10:58 β π 417 π 162 π¬ 9 π 12Hey US-Americans, can you just give Trump Alaska? He wonβt know the difference and might keep him quiet for a bit
21.01.2026 16:01 β π 2 π 1 π¬ 0 π 0βagain! again!β
18.01.2026 21:08 β π 0 π 0 π¬ 0 π 0OTOH, if things have gone wrong, and you have to use the slide, is it bad form to ask for another go?
18.01.2026 21:07 β π 2 π 0 π¬ 0 π 0βdo you even lift bro?β
18.01.2026 20:56 β π 7 π 0 π¬ 0 π 0#QOTD
βI never said even a fraction of the shit thatβs ascribed to meβ
β π΄πππππ‘ πΈπππ π‘πππ
that was sister sledge
17.01.2026 11:06 β π 0 π 0 π¬ 0 π 0Woke up to this sight
16.01.2026 20:26 β π 4 π 0 π¬ 0 π 0hey everyone!
I won the knowbell prize!
Kids are really cute when theyβre at that age where they havenβt yet worked out that giving you their snack means less for them
16.01.2026 15:49 β π 2 π 0 π¬ 0 π 0Just cross off the last digit and take twice the last digit from whatβs left
butβ¦I usually combine with ad hoc techniques. Likeβ¦oh the number ends in 3, so add 7 and cross off the final 0.
never mind, was just responding but it went away so I posted anyway. obvs a silly reply but you answered my question
14.01.2026 16:38 β π 1 π 0 π¬ 1 π 0hey @johnbull.wtf you canβt just post this and delete it!
14.01.2026 16:34 β π 1 π 0 π¬ 1 π 0A second hand yacht? Really? How poor do they think we are?
14.01.2026 16:30 β π 3 π 0 π¬ 0 π 0so how hard are these ErdΓΆs problems anyway?
14.01.2026 16:24 β π 1 π 0 π¬ 0 π 0Land line
analogue tape
analogue clock
real life
it would be interesting to check exactly what happens if you do fractional FT to your two functions, then multiply and transform back. I expect convolution combined with a complex exponential exp(iaxy)
12.01.2026 14:32 β π 1 π 0 π¬ 0 π 0so convolution is replaced by scaling your function by exp(iax) before convolving
12.01.2026 14:29 β π 1 π 0 π¬ 1 π 0convolution is linear combinations of translations.
Or, the infinitesimal generator (d/dx) of translations.
Fractional FT replaces by cos(theta)X+sin(theta)(d/dx)
or, in non-infinitesimal form, the translation operator is replaced by
f(x)->exp(iusx)f(x+uc)
for parameter u.
Another aspect on fractional Fourier transforms. Its generator is the same as the quantum harmonic oscillator, so they are the same as time evolution of the quantum system!
12.01.2026 13:58 β π 2 π 1 π¬ 0 π 0In Quantum Mechanics, Fourier transforms are used to convert between position (X) and momentum (P) space.
Defining a mixture,
A(ΞΈ) = X cos ΞΈ + P sin ΞΈ
then the fractional Fourier transform converts from position to A(ΞΈ) space (for β=1 in my formula for fractional FT)
Youβre probably familiar with Fourier transforms. But, did you know that it can be viewed as a 90Β° rotation in the time-frequency domain and we can rotate by any angle via fractional Fourier transform.
Explains why applying FT twice gives reflection (rotation by 180Β°).
Ghost fox?
So the other night a fox came up to me with a tennis ball in its mouth. Quite unusual so tried taking a picture, but fumbled trying to select camera app and it was already walking away by the time I was ready.
But why can you see through it?
βjones dualβ to avoid confusion
12.01.2026 10:01 β π 5 π 0 π¬ 0 π 0The hat really made a difference!
11.01.2026 18:29 β π 0 π 0 π¬ 0 π 0