Dan Piponi
@dpiponi.mathstodon.xyz.ap.brid.gy
Disclaimer:
👽 My opinions are not my own. They're beamed to me by aliens
Current life:
🎮 Epic Games
Previous lives:
🍩 PhD in Riemann theta functions
🧬 Glaxo […]
🌉 bridged from ⁂ https://mathstodon.xyz/@dpiponi, follow @ap.brid.gy to interact
👽 My opinions are not my own. They're beamed to me by aliens
Current life:
🎮 Epic Games
Previous lives:
🍩 PhD in Riemann theta functions
🧬 Glaxo […]
🌉 bridged from ⁂ https://mathstodon.xyz/@dpiponi, follow @ap.brid.gy to interact
It's moving around Guatemala City now. Apple Maps claims it's 29,905 miles away which is a reminder of why I think it's OK to ask Fermi questions in job interviews.
December 2, 2025 at 6:37 PM
It's moving around Guatemala City now. Apple Maps claims it's 29,905 miles away which is a reminder of why I think it's OK to ask Fermi questions in job interviews.
My lost AirTag sailed over the Gulf of Mexico and now it's in Guatemala. I wonder if it's about to take a road trip.
November 30, 2025 at 8:30 PM
My lost AirTag sailed over the Gulf of Mexico and now it's in Guatemala. I wonder if it's about to take a road trip.
If you're not seeing the problem, look closely.
Very embarrassing. They still haven't fixed that "chartered" error on the web site.
Very embarrassing. They still haven't fixed that "chartered" error on the web site.
November 29, 2025 at 7:14 PM
If you're not seeing the problem, look closely.
Very embarrassing. They still haven't fixed that "chartered" error on the web site.
Very embarrassing. They still haven't fixed that "chartered" error on the web site.
I made an off by one error subtracting 3 hours from 12am. 😭😂😢😿🤣
November 28, 2025 at 11:42 PM
I made an off by one error subtracting 3 hours from 12am. 😭😂😢😿🤣
And check out this proto-beholder
November 27, 2025 at 10:33 PM
And check out this proto-beholder
When I pick up RPG rules the thing that stands out to me is lists: lists of character classes, skills, magic items, spells, monsters and so on. So when looking for precursors its worth checking out lists as well as fiction and games.
I picked this book up on […]
[Original post on mathstodon.xyz]
I picked this book up on […]
[Original post on mathstodon.xyz]
November 27, 2025 at 10:32 PM
When I pick up RPG rules the thing that stands out to me is lists: lists of character classes, skills, magic items, spells, monsters and so on. So when looking for precursors its worth checking out lists as well as fiction and games.
I picked this book up on […]
[Original post on mathstodon.xyz]
I picked this book up on […]
[Original post on mathstodon.xyz]
Not having grown up in the US I'm not 100% sure what does and doesn't count as "taffy" but it's a great subject for a paper. Connects to the topic of rational tangles that I touched on at my ICFP talk years ago.
https://arxiv.org/abs/2511.19461
https://arxiv.org/abs/2511.19461
November 27, 2025 at 6:04 PM
Not having grown up in the US I'm not 100% sure what does and doesn't count as "taffy" but it's a great subject for a paper. Connects to the topic of rational tangles that I touched on at my ICFP talk years ago.
https://arxiv.org/abs/2511.19461
https://arxiv.org/abs/2511.19461
If I was applying for a PhD today I think the topic I'd pick would be related to random matrices. The content of this paper illustrates why in the most readable summary I've come across […]
[Original post on mathstodon.xyz]
[Original post on mathstodon.xyz]
November 26, 2025 at 3:32 PM
If I was applying for a PhD today I think the topic I'd pick would be related to random matrices. The content of this paper illustrates why in the most readable summary I've come across […]
[Original post on mathstodon.xyz]
[Original post on mathstodon.xyz]
Ooops...on lego.com
November 25, 2025 at 7:12 PM
Ooops...on lego.com
I think I posted a version of this claim before but this one is even more strongly worded. This is from Jon Peterson's "Playing at the World" on the history of RPGs and it's about the rules for resolving combat between combatants in Kriegspiel, an early (19th […]
[Original post on mathstodon.xyz]
[Original post on mathstodon.xyz]
November 24, 2025 at 4:00 PM
I think I posted a version of this claim before but this one is even more strongly worded. This is from Jon Peterson's "Playing at the World" on the history of RPGs and it's about the rules for resolving combat between combatants in Kriegspiel, an early (19th […]
[Original post on mathstodon.xyz]
[Original post on mathstodon.xyz]
Nice wargaming set from 1812. By the father of this chap
https://en.wikipedia.org/wiki/Georg_von_Reisswitz
https://en.wikipedia.org/wiki/Georg_von_Reisswitz
November 22, 2025 at 8:32 PM
Nice wargaming set from 1812. By the father of this chap
https://en.wikipedia.org/wiki/Georg_von_Reisswitz
https://en.wikipedia.org/wiki/Georg_von_Reisswitz
It makes me happy that there are people in the world who, when I idly wonder about something, have already done the research.
The iridescence you see sometimes see in meat, especially bacon, is likely caused by alternating muscle layers acting as a photonic […]
[Original post on mathstodon.xyz]
The iridescence you see sometimes see in meat, especially bacon, is likely caused by alternating muscle layers acting as a photonic […]
[Original post on mathstodon.xyz]
November 20, 2025 at 8:28 PM
It makes me happy that there are people in the world who, when I idly wonder about something, have already done the research.
The iridescence you see sometimes see in meat, especially bacon, is likely caused by alternating muscle layers acting as a photonic […]
[Original post on mathstodon.xyz]
The iridescence you see sometimes see in meat, especially bacon, is likely caused by alternating muscle layers acting as a photonic […]
[Original post on mathstodon.xyz]
Today I learnt about Jenny Hanivers. Excuse me while I go off and have a nightmare.
Meanwhile, enjoy the picture of the Morkoth from the first edition Monster Manual.
Meanwhile, enjoy the picture of the Morkoth from the first edition Monster Manual.
November 19, 2025 at 3:39 AM
Today I learnt about Jenny Hanivers. Excuse me while I go off and have a nightmare.
Meanwhile, enjoy the picture of the Morkoth from the first edition Monster Manual.
Meanwhile, enjoy the picture of the Morkoth from the first edition Monster Manual.
À propos of nothing I just want to say how much I love this cover of Dragon magazine from 1982. Far from the usual sword and sorcery material it almost feels like a photograph from the world of D&D. I can't find any other work by the artist, Dean Morrissey, that I like.
November 12, 2025 at 3:33 PM
À propos of nothing I just want to say how much I love this cover of Dragon magazine from 1982. Far from the usual sword and sorcery material it almost feels like a photograph from the world of D&D. I can't find any other work by the artist, Dean Morrissey, that I like.
It's very silly but often when I see a photo (or movie/TV scene) I'm tempted to use tools like Google maps to track down the exact location.
Anyway, my reading is a random walk through book-space and I find myself reading a kids' book about magic cats […]
[Original post on mathstodon.xyz]
Anyway, my reading is a random walk through book-space and I find myself reading a kids' book about magic cats […]
[Original post on mathstodon.xyz]
November 10, 2025 at 2:33 AM
It's very silly but often when I see a photo (or movie/TV scene) I'm tempted to use tools like Google maps to track down the exact location.
Anyway, my reading is a random walk through book-space and I find myself reading a kids' book about magic cats […]
[Original post on mathstodon.xyz]
Anyway, my reading is a random walk through book-space and I find myself reading a kids' book about magic cats […]
[Original post on mathstodon.xyz]
Now I have a somewhat functioning library for dice game simulation I can do with it one of the things I originally intended.
The crunchier RPGs can lead you to situations where you have to resolve complex fights with many participants and it'd make sense to […]
[Original post on mathstodon.xyz]
The crunchier RPGs can lead you to situations where you have to resolve complex fights with many participants and it'd make sense to […]
[Original post on mathstodon.xyz]
November 9, 2025 at 5:11 PM
Now I have a somewhat functioning library for dice game simulation I can do with it one of the things I originally intended.
The crunchier RPGs can lead you to situations where you have to resolve complex fights with many participants and it'd make sense to […]
[Original post on mathstodon.xyz]
The crunchier RPGs can lead you to situations where you have to resolve complex fights with many participants and it'd make sense to […]
[Original post on mathstodon.xyz]
I can't believe I didn't know this fact before today - it seems so fundamental.
If you have a real symmetric matrix A, and pick some unit vector x, then x.Ax (the Rayleigh quotient) is bounded by the smallest and largest eigenvalues. So what happens if I pick […]
[Original post on mathstodon.xyz]
If you have a real symmetric matrix A, and pick some unit vector x, then x.Ax (the Rayleigh quotient) is bounded by the smallest and largest eigenvalues. So what happens if I pick […]
[Original post on mathstodon.xyz]
November 8, 2025 at 5:17 AM
I can't believe I didn't know this fact before today - it seems so fundamental.
If you have a real symmetric matrix A, and pick some unit vector x, then x.Ax (the Rayleigh quotient) is bounded by the smallest and largest eigenvalues. So what happens if I pick […]
[Original post on mathstodon.xyz]
If you have a real symmetric matrix A, and pick some unit vector x, then x.Ax (the Rayleigh quotient) is bounded by the smallest and largest eigenvalues. So what happens if I pick […]
[Original post on mathstodon.xyz]
A common strategy when implementing arrays that grow at the end is to allocate space for N bytes initially and then when more space is required resize to a block of size AN for some A, typically in the range (1, 2], and then keep reallocating as needed scaling […]
[Original post on mathstodon.xyz]
[Original post on mathstodon.xyz]
November 7, 2025 at 4:44 PM
A common strategy when implementing arrays that grow at the end is to allocate space for N bytes initially and then when more space is required resize to a block of size AN for some A, typically in the range (1, 2], and then keep reallocating as needed scaling […]
[Original post on mathstodon.xyz]
[Original post on mathstodon.xyz]
https://www.lego.com/en-us/product/star-trek-u-s-s-enterprise-ncc-1701-d-10356
Woohoo! An official Lego Spot the cat. And a spaceship for her to live on.
Woohoo! An official Lego Spot the cat. And a spaceship for her to live on.
November 6, 2025 at 8:54 PM
https://www.lego.com/en-us/product/star-trek-u-s-s-enterprise-ncc-1701-d-10356
Woohoo! An official Lego Spot the cat. And a spaceship for her to live on.
Woohoo! An official Lego Spot the cat. And a spaceship for her to live on.
Such a nice paint job, inside and out. At the De Young museum.
October 31, 2025 at 2:37 PM
Such a nice paint job, inside and out. At the De Young museum.
Enjoying watching the marine layer float through the neighbourhood this evening.
October 31, 2025 at 1:38 AM
Enjoying watching the marine layer float through the neighbourhood this evening.
I really like Theorem 1 in this paper:
https://arxiv.org/abs/1106.1465
A well known way to compute the determinant of an n x n matrix (aij) is this:
Write 1, 2, ..., n in a row.
Write 1, 2, ..., n in a row below.
Now join each number in the first row to a […]
[Original post on mathstodon.xyz]
https://arxiv.org/abs/1106.1465
A well known way to compute the determinant of an n x n matrix (aij) is this:
Write 1, 2, ..., n in a row.
Write 1, 2, ..., n in a row below.
Now join each number in the first row to a […]
[Original post on mathstodon.xyz]
October 26, 2025 at 10:24 PM
I really like Theorem 1 in this paper:
https://arxiv.org/abs/1106.1465
A well known way to compute the determinant of an n x n matrix (aij) is this:
Write 1, 2, ..., n in a row.
Write 1, 2, ..., n in a row below.
Now join each number in the first row to a […]
[Original post on mathstodon.xyz]
https://arxiv.org/abs/1106.1465
A well known way to compute the determinant of an n x n matrix (aij) is this:
Write 1, 2, ..., n in a row.
Write 1, 2, ..., n in a row below.
Now join each number in the first row to a […]
[Original post on mathstodon.xyz]
I really like the film The Girl with all the Gifts and it turns out that the book is excellent too. There were enough mentions of (basic) mathematical concepts that I wondered if the author was a mathematician but Mike Carey studied English at Oxford.
This […]
[Original post on mathstodon.xyz]
This […]
[Original post on mathstodon.xyz]
October 25, 2025 at 9:26 PM
I really like the film The Girl with all the Gifts and it turns out that the book is excellent too. There were enough mentions of (basic) mathematical concepts that I wondered if the author was a mathematician but Mike Carey studied English at Oxford.
This […]
[Original post on mathstodon.xyz]
This […]
[Original post on mathstodon.xyz]
Not a full proof but I hope this makes it clear.
October 24, 2025 at 10:42 PM
Not a full proof but I hope this makes it clear.
