Barbara Fantechi
@barbarafantechi.bsky.social
Mathematician, cis woman, bi, het married, parent of adults. Loud in the physical and metaphorical sense.
https://marginalnotesmaths.blogspot.com/
https://marginalnotesmaths.blogspot.com/
Reposted by Barbara Fantechi
It’s wildly disingenuous for @aaron.bsky.team to reply to queries about Sarah Kendzior’s suspension about how they don’t comment publicly on individual users when he knows that we all know that they haven’t even told her privately what the basis for the suspension is
November 11, 2025 at 8:14 PM
It’s wildly disingenuous for @aaron.bsky.team to reply to queries about Sarah Kendzior’s suspension about how they don’t comment publicly on individual users when he knows that we all know that they haven’t even told her privately what the basis for the suspension is
Reposted by Barbara Fantechi
I think the belief by the powerful that "people will put up with many things if you are excellent at math" is incredibly revealing in terms of understanding How We Got Here
November 11, 2025 at 7:14 PM
I think the belief by the powerful that "people will put up with many things if you are excellent at math" is incredibly revealing in terms of understanding How We Got Here
Summaring the problems in every maths department.
I think the belief by the powerful that "people will put up with many things if you are excellent at math" is incredibly revealing in terms of understanding How We Got Here
November 11, 2025 at 9:26 PM
Summaring the problems in every maths department.
Reposted by Barbara Fantechi
"There is no sugarcoating this; a majority of 39 Israeli Knesset members approved in a first reading a bill that effectively mandates courts to impose the death penalty exclusively against Palestinians."
#Israel #Gaza #WestBank #Palestine #Apartheid #Incarceration #Courts #Genocide
#Israel #Gaza #WestBank #Palestine #Apartheid #Incarceration #Courts #Genocide
Israel must immediately halt legislation of discriminatory death penalty bill
In response to the passing of the first reading of a controversial new amendment to the Israeli Penal Law.
www.amnesty.org
November 11, 2025 at 9:23 PM
"There is no sugarcoating this; a majority of 39 Israeli Knesset members approved in a first reading a bill that effectively mandates courts to impose the death penalty exclusively against Palestinians."
#Israel #Gaza #WestBank #Palestine #Apartheid #Incarceration #Courts #Genocide
#Israel #Gaza #WestBank #Palestine #Apartheid #Incarceration #Courts #Genocide
One more excellent piece of advice for research mathematicians! My favourite approach to specialist help is expert coauthors who are, or become, friends.
Unsolicited writing advice, no. 18181999:
"Write what you know" is limiting advice, which leads to limited writing. Instead, know what you're writing about. That means due diligence: good research, wide reading, specialist help and advice if you need it. Stay curious. Try new ideas. No limits.
"Write what you know" is limiting advice, which leads to limited writing. Instead, know what you're writing about. That means due diligence: good research, wide reading, specialist help and advice if you need it. Stay curious. Try new ideas. No limits.
November 11, 2025 at 4:25 PM
One more excellent piece of advice for research mathematicians! My favourite approach to specialist help is expert coauthors who are, or become, friends.
Reposted by Barbara Fantechi
Envisioning a glorious future where Sally Rooney is PM of the UK and Ms. Rachel is POTUS
My god they’re actually going to do it inews.co.uk/news/bbc-und...
BBC under pressure to pull Sally Rooney dramas over vow to fund Palestine Action
Former anti-extremism tsar Lord Walney warns the corporation and book publisher Faber & Faber that they may have to 'break ties' with the Irish author
inews.co.uk
August 19, 2025 at 10:07 AM
Envisioning a glorious future where Sally Rooney is PM of the UK and Ms. Rachel is POTUS
Reposted by Barbara Fantechi
This Thursday I'll be chairing the second @londmathsoc.bsky.social Early Career Researcher Professional Development session, on "Applying for a Grant". There's still time for PhD students and ECRs to signup for the Zoom event. #MathSky
www.lms.ac.uk/events/ECR-C...
www.lms.ac.uk/events/ECR-C...
LMS CPD Session 2: Applying for a Grant | London Mathematical Society
LMS Early Career Researcher Professional Development sessions are free online panel discussions, which are aimed at Early Career Researchers and run by the LMS Early Career Research Committee. Each…
www.lms.ac.uk
November 11, 2025 at 9:16 AM
This Thursday I'll be chairing the second @londmathsoc.bsky.social Early Career Researcher Professional Development session, on "Applying for a Grant". There's still time for PhD students and ECRs to signup for the Zoom event. #MathSky
www.lms.ac.uk/events/ECR-C...
www.lms.ac.uk/events/ECR-C...
Usually the best part of my commute is the walk at the end (see photo).
Today however the bus was full of primary school kids, and halfway up the hill they started singing Sofia by Àlvaro Soler.
I am in my office now and I am still smiling. I may have tanked energy for the whole day.
Today however the bus was full of primary school kids, and halfway up the hill they started singing Sofia by Àlvaro Soler.
I am in my office now and I am still smiling. I may have tanked energy for the whole day.
November 11, 2025 at 8:52 AM
Usually the best part of my commute is the walk at the end (see photo).
Today however the bus was full of primary school kids, and halfway up the hill they started singing Sofia by Àlvaro Soler.
I am in my office now and I am still smiling. I may have tanked energy for the whole day.
Today however the bus was full of primary school kids, and halfway up the hill they started singing Sofia by Àlvaro Soler.
I am in my office now and I am still smiling. I may have tanked energy for the whole day.
Reposted by Barbara Fantechi
The reason why I'm so angry has a lot to do with the lives that will be lost — people are absolutely going to die as a direct result of Senate Democrats folding on health care. It also has a lot to do with the suffering that was endured — people were struggling to get by without food assistance. 🧵
November 11, 2025 at 6:58 AM
The reason why I'm so angry has a lot to do with the lives that will be lost — people are absolutely going to die as a direct result of Senate Democrats folding on health care. It also has a lot to do with the suffering that was endured — people were struggling to get by without food assistance. 🧵
Reposted by Barbara Fantechi
Please sign this excellent letter to Ursula vdL, so she can see that nonsense AI hype is neither true nor appropriate for anybody to believe or spread.
Scientists and scholars in AI and its social impacts call on von der Leyen to retract #AIHype statement.
@olivia.science
@abeba.bsky.social
@irisvanrooij.bsky.social
@alexhanna.bsky.social
@rocher.lc
@danmcquillan.bsky.social
@robin.berjon.com
& many others have signed
www.iccl.ie/press-releas...
@olivia.science
@abeba.bsky.social
@irisvanrooij.bsky.social
@alexhanna.bsky.social
@rocher.lc
@danmcquillan.bsky.social
@robin.berjon.com
& many others have signed
www.iccl.ie/press-releas...
Scientists call on the President of the European Commission to retract AI hype statement
Experts in AI call on the President of the European Commission to retract unscientific AI hype statement she made in the budget speech.
www.iccl.ie
November 10, 2025 at 12:16 PM
Please sign this excellent letter to Ursula vdL, so she can see that nonsense AI hype is neither true nor appropriate for anybody to believe or spread.
Reposted by Barbara Fantechi
Reposted by Barbara Fantechi
Scientists and scholars in AI and its social impacts call on von der Leyen to retract #AIHype statement.
@olivia.science
@abeba.bsky.social
@irisvanrooij.bsky.social
@alexhanna.bsky.social
@rocher.lc
@danmcquillan.bsky.social
@robin.berjon.com
& many others have signed
www.iccl.ie/press-releas...
@olivia.science
@abeba.bsky.social
@irisvanrooij.bsky.social
@alexhanna.bsky.social
@rocher.lc
@danmcquillan.bsky.social
@robin.berjon.com
& many others have signed
www.iccl.ie/press-releas...
Scientists call on the President of the European Commission to retract AI hype statement
Experts in AI call on the President of the European Commission to retract unscientific AI hype statement she made in the budget speech.
www.iccl.ie
November 10, 2025 at 9:48 AM
Scientists and scholars in AI and its social impacts call on von der Leyen to retract #AIHype statement.
@olivia.science
@abeba.bsky.social
@irisvanrooij.bsky.social
@alexhanna.bsky.social
@rocher.lc
@danmcquillan.bsky.social
@robin.berjon.com
& many others have signed
www.iccl.ie/press-releas...
@olivia.science
@abeba.bsky.social
@irisvanrooij.bsky.social
@alexhanna.bsky.social
@rocher.lc
@danmcquillan.bsky.social
@robin.berjon.com
& many others have signed
www.iccl.ie/press-releas...
Reposted by Barbara Fantechi
Maybe I should just excerpt some stuff about congressive / ingressive from Eugenia Cheng and send it to him
November 10, 2025 at 7:59 PM
Maybe I should just excerpt some stuff about congressive / ingressive from Eugenia Cheng and send it to him
Today I
sent three overdue emails
discussed maths with coauthor*
got Covid and flu shots
met therapist
*It turns out what I thought was “easy” is anything but. Of course once it’s all proven nicely the referee will find it trivial.
sent three overdue emails
discussed maths with coauthor*
got Covid and flu shots
met therapist
*It turns out what I thought was “easy” is anything but. Of course once it’s all proven nicely the referee will find it trivial.
November 10, 2025 at 9:10 PM
Today I
sent three overdue emails
discussed maths with coauthor*
got Covid and flu shots
met therapist
*It turns out what I thought was “easy” is anything but. Of course once it’s all proven nicely the referee will find it trivial.
sent three overdue emails
discussed maths with coauthor*
got Covid and flu shots
met therapist
*It turns out what I thought was “easy” is anything but. Of course once it’s all proven nicely the referee will find it trivial.
Reposted by Barbara Fantechi
Right, so maybe a better way to frame the question of the thread is, what are good ways to teach people how to meaningfully contribute w/o setting themselves up as smarter / better / faster / superior?
November 10, 2025 at 6:45 PM
Right, so maybe a better way to frame the question of the thread is, what are good ways to teach people how to meaningfully contribute w/o setting themselves up as smarter / better / faster / superior?
Reposted by Barbara Fantechi
@uniofnottingham.bsky.social permanently suspends all teaching of Modern Languages, Music, Plant Biology, Microbiology, Theology, Agriculture, Food Science, and, ironically, Education. And that's not even the complete list. #Nottingham
Nottingham suspends music, language and nursing courses
University says financial uncertainties continue as government’s proposed student levy will ‘wipe out any benefits’ from rising tuition fees
www.timeshighereducation.com
November 10, 2025 at 5:57 PM
@uniofnottingham.bsky.social permanently suspends all teaching of Modern Languages, Music, Plant Biology, Microbiology, Theology, Agriculture, Food Science, and, ironically, Education. And that's not even the complete list. #Nottingham
Reposted by Barbara Fantechi
I think you can get it from the Pieri rule:
S²V⊗V*≅S²V⊗Λ^{n-1}V⊗D^{-1} where D is the 1-dim determinant rep.
Let W=S^{(3,1,1,...,1,0)}V (Schur functor)
Pieri now gives S²V⊗Λ^{d-1}V≅(D⊗V)⊕W
Tensoring with D^{-1} gives V⊕(D^{-1}W), so the cokernel of your map is always the GL_d irrep D^{-1}W
S²V⊗V*≅S²V⊗Λ^{n-1}V⊗D^{-1} where D is the 1-dim determinant rep.
Let W=S^{(3,1,1,...,1,0)}V (Schur functor)
Pieri now gives S²V⊗Λ^{d-1}V≅(D⊗V)⊕W
Tensoring with D^{-1} gives V⊕(D^{-1}W), so the cokernel of your map is always the GL_d irrep D^{-1}W
November 10, 2025 at 6:37 AM
I think you can get it from the Pieri rule:
S²V⊗V*≅S²V⊗Λ^{n-1}V⊗D^{-1} where D is the 1-dim determinant rep.
Let W=S^{(3,1,1,...,1,0)}V (Schur functor)
Pieri now gives S²V⊗Λ^{d-1}V≅(D⊗V)⊕W
Tensoring with D^{-1} gives V⊕(D^{-1}W), so the cokernel of your map is always the GL_d irrep D^{-1}W
S²V⊗V*≅S²V⊗Λ^{n-1}V⊗D^{-1} where D is the 1-dim determinant rep.
Let W=S^{(3,1,1,...,1,0)}V (Schur functor)
Pieri now gives S²V⊗Λ^{d-1}V≅(D⊗V)⊕W
Tensoring with D^{-1} gives V⊕(D^{-1}W), so the cokernel of your map is always the GL_d irrep D^{-1}W
Why use LLMs when one can ask human beings and get much better answers?
I think you can get it from the Pieri rule:
S²V⊗V*≅S²V⊗Λ^{n-1}V⊗D^{-1} where D is the 1-dim determinant rep.
Let W=S^{(3,1,1,...,1,0)}V (Schur functor)
Pieri now gives S²V⊗Λ^{d-1}V≅(D⊗V)⊕W
Tensoring with D^{-1} gives V⊕(D^{-1}W), so the cokernel of your map is always the GL_d irrep D^{-1}W
S²V⊗V*≅S²V⊗Λ^{n-1}V⊗D^{-1} where D is the 1-dim determinant rep.
Let W=S^{(3,1,1,...,1,0)}V (Schur functor)
Pieri now gives S²V⊗Λ^{d-1}V≅(D⊗V)⊕W
Tensoring with D^{-1} gives V⊕(D^{-1}W), so the cokernel of your map is always the GL_d irrep D^{-1}W
November 10, 2025 at 7:28 AM
Why use LLMs when one can ask human beings and get much better answers?
Reposted by Barbara Fantechi
It's time. If you do (or do not) follow me, do (or do not) study math, and are (or are not) drinking coffee, please send along a #MathCoffeeSelfie and let me know how you've been doing.
November 9, 2025 at 4:16 PM
It's time. If you do (or do not) follow me, do (or do not) study math, and are (or are not) drinking coffee, please send along a #MathCoffeeSelfie and let me know how you've been doing.
Reposted by Barbara Fantechi
My theory about Joyce Carol Oates is that all her bad posts are her charging up like Godzilla's spines until she lets loose with a radioactive blast that leaves the world's richest Nazi a pile of ash
November 9, 2025 at 2:31 PM
My theory about Joyce Carol Oates is that all her bad posts are her charging up like Godzilla's spines until she lets loose with a radioactive blast that leaves the world's richest Nazi a pile of ash
No cat has been harmed for this picture.
Buona domenica!
Buona domenica!
November 9, 2025 at 1:57 PM
No cat has been harmed for this picture.
Buona domenica!
Buona domenica!
Reposted by Barbara Fantechi
did you know that intercountry #adoptees born before 1983 have no guarantee of US citizenship, and instead are treated as immigrants who must obtain citizenship through naturalization? That they are subject to deportation if they have committed a crime or are deemed to be in the US “illegally?”
November 9, 2025 at 1:28 PM
did you know that intercountry #adoptees born before 1983 have no guarantee of US citizenship, and instead are treated as immigrants who must obtain citizenship through naturalization? That they are subject to deportation if they have committed a crime or are deemed to be in the US “illegally?”
#LinearAlgebra #AlgebraicGeometry #MathSky
Let V be a vector space, dim V = d.
The map V⊗V→S²V induces
f:V→S²V⊗V*.
If d=2, coker f = (canonically isomorphic to) S³V⊗Λ²V*.
If d=3, coker f =Λ²S²V⊗Λ³V*.
This is a key step in a paper I am currently writing.
1/3
Let V be a vector space, dim V = d.
The map V⊗V→S²V induces
f:V→S²V⊗V*.
If d=2, coker f = (canonically isomorphic to) S³V⊗Λ²V*.
If d=3, coker f =Λ²S²V⊗Λ³V*.
This is a key step in a paper I am currently writing.
1/3
November 9, 2025 at 1:37 PM
#LinearAlgebra #AlgebraicGeometry #MathSky
Let V be a vector space, dim V = d.
The map V⊗V→S²V induces
f:V→S²V⊗V*.
If d=2, coker f = (canonically isomorphic to) S³V⊗Λ²V*.
If d=3, coker f =Λ²S²V⊗Λ³V*.
This is a key step in a paper I am currently writing.
1/3
Let V be a vector space, dim V = d.
The map V⊗V→S²V induces
f:V→S²V⊗V*.
If d=2, coker f = (canonically isomorphic to) S³V⊗Λ²V*.
If d=3, coker f =Λ²S²V⊗Λ³V*.
This is a key step in a paper I am currently writing.
1/3
For those who can’t access the image: it’s the text of the poem Suicide in the Trenches, by Siegfried Sassoon
en.wikisource.org/wiki/Counter...
en.wikisource.org/wiki/Counter...
November 9, 2025 at 1:13 PM
For those who can’t access the image: it’s the text of the poem Suicide in the Trenches, by Siegfried Sassoon
en.wikisource.org/wiki/Counter...
en.wikisource.org/wiki/Counter...
Reposted by Barbara Fantechi
On the death of James Watson
So James Watson, a deeply unsavoury individual who co-won a Nobel Prize by stealing Rosalind Franklin’s ground breaking research on DNA, and was an unrepentant racist and misogynist, is dead. Lest it be forgotten, here is a collection of authentic quotes that give an…
So James Watson, a deeply unsavoury individual who co-won a Nobel Prize by stealing Rosalind Franklin’s ground breaking research on DNA, and was an unrepentant racist and misogynist, is dead. Lest it be forgotten, here is a collection of authentic quotes that give an…
On the death of James Watson
So James Watson, a deeply unsavoury individual who co-won a Nobel Prize by stealing Rosalind Franklin’s ground breaking research on DNA, and was an unrepentant racist and misogynist, is dead. Lest it be forgotten, here is a collection of authentic quotes that give an insight into his true character.
telescoper.blog
November 9, 2025 at 12:27 PM
On the death of James Watson
So James Watson, a deeply unsavoury individual who co-won a Nobel Prize by stealing Rosalind Franklin’s ground breaking research on DNA, and was an unrepentant racist and misogynist, is dead. Lest it be forgotten, here is a collection of authentic quotes that give an…
So James Watson, a deeply unsavoury individual who co-won a Nobel Prize by stealing Rosalind Franklin’s ground breaking research on DNA, and was an unrepentant racist and misogynist, is dead. Lest it be forgotten, here is a collection of authentic quotes that give an…