Michael Kinyon
@profkinyon.bsky.social
Mathematics professor at the University of Denver. Quasigroups, Semigroups, Automated Deduction. He/Him. Occasionally drop in at Mathstodon, but not as much as I used to.
Existential horror
December 12, 2025 at 8:05 PM
Existential horror
Because they learned in previous classes that it's where they will get the most points taken off.
Never understand why students are so averse to simplifying their work as they go. It will make your life so much easier I promise.
December 12, 2025 at 5:26 PM
Because they learned in previous classes that it's where they will get the most points taken off.
I wonder who will voice me in the anime adaptation of my life
December 12, 2025 at 4:48 PM
I wonder who will voice me in the anime adaptation of my life
Brazil, where hearts were entertaining June
We stood beneath an amber moon
And softly murmured "someday soon."
We stood beneath an amber moon
And softly murmured "someday soon."
December 12, 2025 at 3:42 AM
Brazil, where hearts were entertaining June
We stood beneath an amber moon
And softly murmured "someday soon."
We stood beneath an amber moon
And softly murmured "someday soon."
"It turns out that" does a lot of heavy lifting in mathematics.
December 11, 2025 at 7:10 PM
"It turns out that" does a lot of heavy lifting in mathematics.
I guess it's time I confess, I'm just an LLM.
(Largely Loony Michael)
(Largely Loony Michael)
December 10, 2025 at 11:51 PM
I guess it's time I confess, I'm just an LLM.
(Largely Loony Michael)
(Largely Loony Michael)
Reposted by Michael Kinyon
George Boole died on this day in 1864. en.wikipedia.org/wiki/George_...
His biographer Des MacHale left these flowers at his grave today. en.wikipedia.org/wiki/Des_Mac...
His biographer Des MacHale left these flowers at his grave today. en.wikipedia.org/wiki/Des_Mac...
December 8, 2025 at 7:49 PM
George Boole died on this day in 1864. en.wikipedia.org/wiki/George_...
His biographer Des MacHale left these flowers at his grave today. en.wikipedia.org/wiki/Des_Mac...
His biographer Des MacHale left these flowers at his grave today. en.wikipedia.org/wiki/Des_Mac...
Movie you’ve watched more than six times with a gif.
Hard mode: no Stars (Wars nor Trek), LOTR, or Marvel, Disney Animated or Pixar.
Hard mode: no Stars (Wars nor Trek), LOTR, or Marvel, Disney Animated or Pixar.
December 8, 2025 at 4:50 AM
Movie you’ve watched more than six times with a gif.
Hard mode: no Stars (Wars nor Trek), LOTR, or Marvel, Disney Animated or Pixar.
Hard mode: no Stars (Wars nor Trek), LOTR, or Marvel, Disney Animated or Pixar.
I was the shadow of the waxwing slain
By the false azure in the windowpane
By the false azure in the windowpane
Which lines of poetry live rent-free in your head?
December 7, 2025 at 9:42 PM
I was the shadow of the waxwing slain
By the false azure in the windowpane
By the false azure in the windowpane
Every day I am thankful that all it takes to verify my humanity is my ability to check a box.
December 7, 2025 at 8:30 PM
Every day I am thankful that all it takes to verify my humanity is my ability to check a box.
I much prefer being mistaken over being incorrect, and I prefer being incorrect over being wrong.
On the other hand, if I'm right, I'm right.
On the other hand, if I'm right, I'm right.
December 6, 2025 at 9:05 PM
I much prefer being mistaken over being incorrect, and I prefer being incorrect over being wrong.
On the other hand, if I'm right, I'm right.
On the other hand, if I'm right, I'm right.
Typical instructions for algebra exercises:
"Simplify the following expressions. Assume that all variables are positive."
That second sentence is so important, and so often ignored or forgotten.
(Context: I just graded exams and every student simplified sqrt(x^2) to x instead of |x|.)
"Simplify the following expressions. Assume that all variables are positive."
That second sentence is so important, and so often ignored or forgotten.
(Context: I just graded exams and every student simplified sqrt(x^2) to x instead of |x|.)
November 24, 2025 at 11:26 PM
Typical instructions for algebra exercises:
"Simplify the following expressions. Assume that all variables are positive."
That second sentence is so important, and so often ignored or forgotten.
(Context: I just graded exams and every student simplified sqrt(x^2) to x instead of |x|.)
"Simplify the following expressions. Assume that all variables are positive."
That second sentence is so important, and so often ignored or forgotten.
(Context: I just graded exams and every student simplified sqrt(x^2) to x instead of |x|.)
I hope my coauthor shares my optimism.
November 22, 2025 at 7:02 PM
I hope my coauthor shares my optimism.
At one of those "clarity vs elegance" junctures in my writing of this paper. I'm greedy though, so I hope I'll figure out how to have both.
November 21, 2025 at 9:01 PM
At one of those "clarity vs elegance" junctures in my writing of this paper. I'm greedy though, so I hope I'll figure out how to have both.
While considering a purchase, I asked "how much does the free trial cost?" so now I have to walk from Denver into the Pacific Ocean.
November 20, 2025 at 8:18 PM
While considering a purchase, I asked "how much does the free trial cost?" so now I have to walk from Denver into the Pacific Ocean.
Reading a paper that denotes the kernel of a mapping f by
"ker f" but the kernel of a mapping n is denoted by "kern".
"ker f" but the kernel of a mapping n is denoted by "kern".
November 18, 2025 at 5:53 PM
Reading a paper that denotes the kernel of a mapping f by
"ker f" but the kernel of a mapping n is denoted by "kern".
"ker f" but the kernel of a mapping n is denoted by "kern".
K: Have you considered consulting a doctor about that?
Me: I am a doctor. I have a PhD in mathematics
K: No, I meant
Me: and therefore I am an expert in all scientific disciplines
Me: I am a doctor. I have a PhD in mathematics
K: No, I meant
Me: and therefore I am an expert in all scientific disciplines
November 14, 2025 at 5:56 PM
K: Have you considered consulting a doctor about that?
Me: I am a doctor. I have a PhD in mathematics
K: No, I meant
Me: and therefore I am an expert in all scientific disciplines
Me: I am a doctor. I have a PhD in mathematics
K: No, I meant
Me: and therefore I am an expert in all scientific disciplines
You kids and your six trig functions. Back in my day we had only one, and we used it for everything.
sin(θ)
sin(π/2 - θ)
sin(θ)/sin(π/2 - θ)
1/sin(θ)
1/sin(π/2 - θ)
sin(π/2 - θ)/sin(θ)
sin(θ)
sin(π/2 - θ)
sin(θ)/sin(π/2 - θ)
1/sin(θ)
1/sin(π/2 - θ)
sin(π/2 - θ)/sin(θ)
November 7, 2025 at 12:15 AM
You kids and your six trig functions. Back in my day we had only one, and we used it for everything.
sin(θ)
sin(π/2 - θ)
sin(θ)/sin(π/2 - θ)
1/sin(θ)
1/sin(π/2 - θ)
sin(π/2 - θ)/sin(θ)
sin(θ)
sin(π/2 - θ)
sin(θ)/sin(π/2 - θ)
1/sin(θ)
1/sin(π/2 - θ)
sin(π/2 - θ)/sin(θ)
a∈A
{a}⊆A
{a}∈𝒫(A)
*sigh*
{a}⊆A
{a}∈𝒫(A)
*sigh*
November 4, 2025 at 3:39 AM
a∈A
{a}⊆A
{a}∈𝒫(A)
*sigh*
{a}⊆A
{a}∈𝒫(A)
*sigh*
I've been in academia for about 33 years, but even today when I hear or read "P.I.", my brain first thinks of Tom Selleck.
November 2, 2025 at 1:15 AM
I've been in academia for about 33 years, but even today when I hear or read "P.I.", my brain first thinks of Tom Selleck.
Our dog freaks out whenever she hears the doorbell.
Trick-or-treating in this neighborhood starts soon.
It's going to be an interesting evening.
Trick-or-treating in this neighborhood starts soon.
It's going to be an interesting evening.
October 31, 2025 at 11:15 PM
Our dog freaks out whenever she hears the doorbell.
Trick-or-treating in this neighborhood starts soon.
It's going to be an interesting evening.
Trick-or-treating in this neighborhood starts soon.
It's going to be an interesting evening.
Reposted by Michael Kinyon
arxiv.org/abs/2510.19961
/Loops with squares in two nuclei/
Michael Kinyon (@profkinyon.bsky.social) , J.D. Phillips
/Loops with squares in two nuclei/
Michael Kinyon (@profkinyon.bsky.social) , J.D. Phillips
October 24, 2025 at 3:27 AM
arxiv.org/abs/2510.19961
/Loops with squares in two nuclei/
Michael Kinyon (@profkinyon.bsky.social) , J.D. Phillips
/Loops with squares in two nuclei/
Michael Kinyon (@profkinyon.bsky.social) , J.D. Phillips
The more coauthors a paper has, the more typos it will have.
It seems counterintuitive but each author assumes the others are the ones responsible for carefully checking everything.
It seems counterintuitive but each author assumes the others are the ones responsible for carefully checking everything.
October 22, 2025 at 5:04 PM
The more coauthors a paper has, the more typos it will have.
It seems counterintuitive but each author assumes the others are the ones responsible for carefully checking everything.
It seems counterintuitive but each author assumes the others are the ones responsible for carefully checking everything.
Abel's line "it appears to me that this theorem admits exceptions" is one of my favorite sentences in the history of mathematics.
Working on the TRIUMPHS project on Abel and Cauchy's approaches to infinite series with my real analysis honors student. We have decided that Abel is totally a hater. #MathSky
digitalcommons.ursinus.edu/triumphs_ana...
digitalcommons.ursinus.edu/triumphs_ana...
Abel and Cauchy on a Rigorous Approach to Infinite Series
By Dave Ruch, Published on 01/01/17
digitalcommons.ursinus.edu
October 21, 2025 at 8:29 PM
Abel's line "it appears to me that this theorem admits exceptions" is one of my favorite sentences in the history of mathematics.
Given a ladder, if:
* you know how to get on the first step, and
* if you're on a step, you know how to get on the next one,
then you know how to climb the ladder. #induction
* you know how to get on the first step, and
* if you're on a step, you know how to get on the next one,
then you know how to climb the ladder. #induction
October 21, 2025 at 3:00 PM
Given a ladder, if:
* you know how to get on the first step, and
* if you're on a step, you know how to get on the next one,
then you know how to climb the ladder. #induction
* you know how to get on the first step, and
* if you're on a step, you know how to get on the next one,
then you know how to climb the ladder. #induction