Maarten van Dijk
@maavdijk.bsky.social
Mathematics master student at Utrecht University, 25 years old
Pinned
Maarten van Dijk
@maavdijk.bsky.social
· Nov 21
Hi everyone! I come from Twitter to here, here for #mathsky however I am usually not one posting content myself. I do love to read all about what others are doing. Did my bachelors in Utrecht and now doing the masters. Soon starting with my masters thesis :)
Reposted by Maarten van Dijk
"Let us join forces to build a future that is not only desirable but also truly worth striving for—one grounded in common sense rather than automated thoughtlessness"
Open letter to Dutch government and forming parties
Join me in signing 🖊️ 🙏 openletter.earth/zorgvuldig-a...
Open letter to Dutch government and forming parties
Join me in signing 🖊️ 🙏 openletter.earth/zorgvuldig-a...
Thoughtfully Shaping Our Digital Future
openletter.earth
December 13, 2025 at 7:59 PM
"Let us join forces to build a future that is not only desirable but also truly worth striving for—one grounded in common sense rather than automated thoughtlessness"
Open letter to Dutch government and forming parties
Join me in signing 🖊️ 🙏 openletter.earth/zorgvuldig-a...
Open letter to Dutch government and forming parties
Join me in signing 🖊️ 🙏 openletter.earth/zorgvuldig-a...
Reposted by Maarten van Dijk
Handed in my masters thesis yesterday. Loved the research part, the writing I enjoyed a little less. We'll see how it will be graded but the project was fun to do
December 6, 2025 at 12:14 PM
Handed in my masters thesis yesterday. Loved the research part, the writing I enjoyed a little less. We'll see how it will be graded but the project was fun to do
Reposted by Maarten van Dijk
What I appreciate the most about math research is that the only thing you need to care about is the math itself. No need to worry about not enough people responding to your survey, the risk of blowing up a lab, acquiring rare/expensive materials/equipment etc. Just math.
#MathSky
#MathSky
October 6, 2025 at 1:56 PM
What I appreciate the most about math research is that the only thing you need to care about is the math itself. No need to worry about not enough people responding to your survey, the risk of blowing up a lab, acquiring rare/expensive materials/equipment etc. Just math.
#MathSky
#MathSky
Reposted by Maarten van Dijk
I'm about to publish my first coauthored paper soon. I only contributed 3-4 pages out of ~20, but it still feels surreal. Just a year ago I didn't think any mathematician would've seen something in me to give me this opportunity, especially considering my undergrad grades.
(1/4)
(1/4)
September 14, 2025 at 9:09 PM
I'm about to publish my first coauthored paper soon. I only contributed 3-4 pages out of ~20, but it still feels surreal. Just a year ago I didn't think any mathematician would've seen something in me to give me this opportunity, especially considering my undergrad grades.
(1/4)
(1/4)
Reposted by Maarten van Dijk
I had 38 seconds on the clock when I got to this position in a bullet game. Can you find the forced checkmate within this time? (I didn't - chat, am I cooked?)
#chesspunks
#chesspunks
August 30, 2025 at 3:59 PM
I had 38 seconds on the clock when I got to this position in a bullet game. Can you find the forced checkmate within this time? (I didn't - chat, am I cooked?)
#chesspunks
#chesspunks
Reposted by Maarten van Dijk
I don't understand the intuition behind comultiplication in (co/bi)algebras. Yes I'm aware that it's the dual of multiplication, but categorical duality means nothing to me in terms of intuition. Is there a better explanation of how to find an expression for Δ(x) given μ?
#mathsky
#mathsky
![Comultiplication in \mathbb{C}[x] is given by
\Delta(x^n) = \sum_{i=1}^{n} x^i \otimes x^{n-i}
which is what I don't get - this formula seems pulled out of a hat to me.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:uvxvfsgazd747andogtpg3bu/bafkreih4bvwgyoeewauoav6orfhrnhz65etsyody6zxjh4lhdubmdb6acy@jpeg)
August 11, 2025 at 4:44 PM
I don't understand the intuition behind comultiplication in (co/bi)algebras. Yes I'm aware that it's the dual of multiplication, but categorical duality means nothing to me in terms of intuition. Is there a better explanation of how to find an expression for Δ(x) given μ?
#mathsky
#mathsky
Reposted by Maarten van Dijk
Reposted by Maarten van Dijk
🌻🦋🌻
August 1, 2025 at 4:33 AM
🌻🦋🌻
Reposted by Maarten van Dijk
Symmetric function theorists:
Since the plethystic substitution & evaluation maps don't commute in general due to an extra factor of (-1)^n involved when evaluating the plethysm of a negation (a problem when n is odd), would a characteristic 2 setting solve this problem?
#MathSky #AlgComb
Since the plethystic substitution & evaluation maps don't commute in general due to an extra factor of (-1)^n involved when evaluating the plethysm of a negation (a problem when n is odd), would a characteristic 2 setting solve this problem?
#MathSky #AlgComb
July 9, 2025 at 7:17 PM
Reposted by Maarten van Dijk
ik bluesky isn't the best place for this but I really wanna find this earworm. All I know is that it's probably mando/canto/J-pop, in B♭ major, and notoriously repeats the chord progression
Ia-Vb-via-Ic-IVa-Ib-ii7a-Va
with these exact inversions throughout the whole song. Ideas?
Ia-Vb-via-Ic-IVa-Ib-ii7a-Va
with these exact inversions throughout the whole song. Ideas?
July 6, 2025 at 1:06 PM
ik bluesky isn't the best place for this but I really wanna find this earworm. All I know is that it's probably mando/canto/J-pop, in B♭ major, and notoriously repeats the chord progression
Ia-Vb-via-Ic-IVa-Ib-ii7a-Va
with these exact inversions throughout the whole song. Ideas?
Ia-Vb-via-Ic-IVa-Ib-ii7a-Va
with these exact inversions throughout the whole song. Ideas?
Reposted by Maarten van Dijk
I hate YouTube's automatic translations because they often suck and I don't know how to turn them off
I don't think this guy was literally murdered in front of the judge. That seems unlikely
I don't think this guy was literally murdered in front of the judge. That seems unlikely
June 26, 2025 at 11:07 PM
I hate YouTube's automatic translations because they often suck and I don't know how to turn them off
I don't think this guy was literally murdered in front of the judge. That seems unlikely
I don't think this guy was literally murdered in front of the judge. That seems unlikely
Reposted by Maarten van Dijk
i HATEEEEE to do this, but this is all i currently have to my name, so if you enjoy my posts at ALL and wanna support a struggling grad student, please share and/or give what you can 🥹
v e n m o: astrojaz
p a y p a l: www.paypal.me/Spacequeenjaz
v e n m o: astrojaz
p a y p a l: www.paypal.me/Spacequeenjaz
June 25, 2025 at 9:53 PM
i HATEEEEE to do this, but this is all i currently have to my name, so if you enjoy my posts at ALL and wanna support a struggling grad student, please share and/or give what you can 🥹
v e n m o: astrojaz
p a y p a l: www.paypal.me/Spacequeenjaz
v e n m o: astrojaz
p a y p a l: www.paypal.me/Spacequeenjaz
Reposted by Maarten van Dijk
Btw if you read this far give this post (not the first one) a like. Bluesky is notorious for only showing people the first message in a thread and consequently people only interact with the first message, so I want to see how many people actually read the whole thing.
That's all for now.
(12/12)
That's all for now.
(12/12)
June 24, 2025 at 12:08 PM
Btw if you read this far give this post (not the first one) a like. Bluesky is notorious for only showing people the first message in a thread and consequently people only interact with the first message, so I want to see how many people actually read the whole thing.
That's all for now.
(12/12)
That's all for now.
(12/12)
Reposted by Maarten van Dijk
Oh yeah so I turned 22 yesterday. I don't usually like birthdays because it's a painful reminder that I've yet again wasted another year of my life accomplishing nothing. I'm working hard on changing that though, which is why I haven't been posting much lately.
(1/12)
(1/12)
June 24, 2025 at 12:07 PM
Oh yeah so I turned 22 yesterday. I don't usually like birthdays because it's a painful reminder that I've yet again wasted another year of my life accomplishing nothing. I'm working hard on changing that though, which is why I haven't been posting much lately.
(1/12)
(1/12)
Reposted by Maarten van Dijk
I submitted finalish drafts of Chapters 1-6 of "Visual Algebra" to the AMS, and have stable drafts of the other chapters. Is anyone interesting in reviewing it? Either formally or informally.
I'm sure the AMS offers something for such a service, like book credit.
1/2
I'm sure the AMS offers something for such a service, like book credit.
1/2
June 18, 2025 at 7:59 PM
I submitted finalish drafts of Chapters 1-6 of "Visual Algebra" to the AMS, and have stable drafts of the other chapters. Is anyone interesting in reviewing it? Either formally or informally.
I'm sure the AMS offers something for such a service, like book credit.
1/2
I'm sure the AMS offers something for such a service, like book credit.
1/2
Reposted by Maarten van Dijk
My institute, Kavli-IPMU at the university of Tokyo is hiring early career researchers whose work has been disrupted due to difficult circumstances due to events happening at various places currently in the world. Please repost and encourage them to apply. 🙏🏻 www.ipmu.jp/en/job-oppor...
Special Postdoctoral Positions for displaced scientists (2025)
The Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), WPI at the University of Tokyo solicits applications for its special Postdoctoral Fellowship program.
www.ipmu.jp
June 8, 2025 at 3:07 PM
My institute, Kavli-IPMU at the university of Tokyo is hiring early career researchers whose work has been disrupted due to difficult circumstances due to events happening at various places currently in the world. Please repost and encourage them to apply. 🙏🏻 www.ipmu.jp/en/job-oppor...
Reposted by Maarten van Dijk
oh no, we hebben again een serieus probleem
June 2, 2025 at 8:07 PM
oh no, we hebben again een serieus probleem
Reposted by Maarten van Dijk
Think imma do a Q&A
I'll try to answer all questions over the next week or so, but if I don't like the question (e.g. because it's too personal) then I'll skip it
ngl.link/totientquoti...
I'll try to answer all questions over the next week or so, but if I don't like the question (e.g. because it's too personal) then I'll skip it
ngl.link/totientquoti...
May 19, 2025 at 9:10 AM
Think imma do a Q&A
I'll try to answer all questions over the next week or so, but if I don't like the question (e.g. because it's too personal) then I'll skip it
ngl.link/totientquoti...
I'll try to answer all questions over the next week or so, but if I don't like the question (e.g. because it's too personal) then I'll skip it
ngl.link/totientquoti...
Reposted by Maarten van Dijk
In graph theory, there is something called "Scheinerman's conjecture." It was proven in 2009, so it's not a conjecture anymore, but it's been known by that name for so long that nobody wants to call it anything else.
May 1, 2025 at 8:44 PM
In graph theory, there is something called "Scheinerman's conjecture." It was proven in 2009, so it's not a conjecture anymore, but it's been known by that name for so long that nobody wants to call it anything else.
I have been working with Chebyshev polynomials a lot recently. I barely know any other polynomials anymore
April 25, 2025 at 2:58 PM
I have been working with Chebyshev polynomials a lot recently. I barely know any other polynomials anymore
Reposted by Maarten van Dijk
Any piano teachers here willing to help me for money? I can't do lessons but I do think being able to commission audio would help me.
April 6, 2025 at 7:19 PM
Any piano teachers here willing to help me for money? I can't do lessons but I do think being able to commission audio would help me.
Reposted by Maarten van Dijk
#AcademicSky
I'm so tired of being misunderstood. Every time I talk about how people should be more sympathetic to those struggling in an intense program, people reply with accusations of elitism and privilege blindness. They then double down on how I fully deserved to struggle,
1/2
I'm so tired of being misunderstood. Every time I talk about how people should be more sympathetic to those struggling in an intense program, people reply with accusations of elitism and privilege blindness. They then double down on how I fully deserved to struggle,
1/2
April 9, 2025 at 8:57 PM
#AcademicSky
I'm so tired of being misunderstood. Every time I talk about how people should be more sympathetic to those struggling in an intense program, people reply with accusations of elitism and privilege blindness. They then double down on how I fully deserved to struggle,
1/2
I'm so tired of being misunderstood. Every time I talk about how people should be more sympathetic to those struggling in an intense program, people reply with accusations of elitism and privilege blindness. They then double down on how I fully deserved to struggle,
1/2