Henry Towsner
@substitutedepsilon.bsky.social
Associate professor of mathematics at UPenn. Logic and related topics. Sometimes distracted by RPGs and Judaism. He/him/his.
The power of material implication is in convincing the four year old that since annis hags aren’t real, that means if they meet an annis hag then they’ll be able to do real magic to escape it.
November 6, 2025 at 2:53 PM
The power of material implication is in convincing the four year old that since annis hags aren’t real, that means if they meet an annis hag then they’ll be able to do real magic to escape it.
A colleague discussed his notes from a meeting about a new policy with me; next to the words "hopes and fears" on the handout was a little note of what had been said at the meeting - "blow it all up".
He clarified that this was a hope.
He clarified that this was a hope.
September 10, 2025 at 7:34 PM
A colleague discussed his notes from a meeting about a new policy with me; next to the words "hopes and fears" on the handout was a little note of what had been said at the meeting - "blow it all up".
He clarified that this was a hope.
He clarified that this was a hope.
The four year old persuaded me to run a D&D module for them as a 'choose your own adventure' type game.
They proceeded to ignore every plot hook but found a random NPC and decided they were best friends now. Clearly a natural gamer.
They proceeded to ignore every plot hook but found a random NPC and decided they were best friends now. Clearly a natural gamer.
June 12, 2025 at 2:22 PM
The four year old persuaded me to run a D&D module for them as a 'choose your own adventure' type game.
They proceeded to ignore every plot hook but found a random NPC and decided they were best friends now. Clearly a natural gamer.
They proceeded to ignore every plot hook but found a random NPC and decided they were best friends now. Clearly a natural gamer.
There’s a specific sense of dread that comes with picking your child up from preschool and seeing that a third of the class didn’t show up today.
February 1, 2025 at 2:52 AM
There’s a specific sense of dread that comes with picking your child up from preschool and seeing that a third of the class didn’t show up today.
Playing “the zoo game” with four kids 3-6. One wants constant attention for how scary their animal is, one wants constant attention for how pretty their animal is, one wants to sit in a corner loudly saying ‘Gooba’ nonstop, and one just wants to lick everything.
This is vampire larp all over again.
This is vampire larp all over again.
December 26, 2024 at 12:49 AM
Playing “the zoo game” with four kids 3-6. One wants constant attention for how scary their animal is, one wants constant attention for how pretty their animal is, one wants to sit in a corner loudly saying ‘Gooba’ nonstop, and one just wants to lick everything.
This is vampire larp all over again.
This is vampire larp all over again.
The answer, which maybe I should have guessed, is that these are exactly de Bruijn indices described differently.
Has anyone seen a syntax in which free variables can be "protected" from binders, so that binding a protected copy of a free variable strips off a layer of protection (so a further binder can now bind it) without binding the variable?
December 4, 2024 at 3:55 PM
The answer, which maybe I should have guessed, is that these are exactly de Bruijn indices described differently.
Has anyone seen a syntax in which free variables can be "protected" from binders, so that binding a protected copy of a free variable strips off a layer of protection (so a further binder can now bind it) without binding the variable?
November 26, 2024 at 4:58 PM
Has anyone seen a syntax in which free variables can be "protected" from binders, so that binding a protected copy of a free variable strips off a layer of protection (so a further binder can now bind it) without binding the variable?
My current pet peeve is the use of “syllabus” like it has a clear, field independent meaning.
Is my policy on food in the classroom actually what’s needed to decide about transfer credit, or is there some other piece of information being sought that could be specifically named?
Is my policy on food in the classroom actually what’s needed to decide about transfer credit, or is there some other piece of information being sought that could be specifically named?
November 24, 2024 at 3:43 PM
My current pet peeve is the use of “syllabus” like it has a clear, field independent meaning.
Is my policy on food in the classroom actually what’s needed to decide about transfer credit, or is there some other piece of information being sought that could be specifically named?
Is my policy on food in the classroom actually what’s needed to decide about transfer credit, or is there some other piece of information being sought that could be specifically named?
There are so many books about how meaningful writing is, and songs about the power of music, but somehow math about math is always about what math *can't* do.
May 23, 2024 at 8:05 PM
There are so many books about how meaningful writing is, and songs about the power of music, but somehow math about math is always about what math *can't* do.
On the one hand, kids should learn the Passover story in an age appropriate way, and on the other hand, maybe next year the sea life they encountered in the Red Sea will occupy a less central place in our family’s telling of the story.
April 28, 2024 at 1:26 PM
On the one hand, kids should learn the Passover story in an age appropriate way, and on the other hand, maybe next year the sea life they encountered in the Red Sea will occupy a less central place in our family’s telling of the story.