Category Archives: category theory

Readers wanted!

Posted on August 10, 2014 by Brent

tl;dr: Read a draft of my thesis and send me your feedback by September 9! Over the past year I’ve had several people say things along the lines of, “let me know if you want me to read through your … Continue reading →

Posted in category theory, combinatorics, diagrams, grad school, math, species, writing | Tagged , , , , | 15 Comments

Anafunctors

Posted on June 16, 2014 by Brent

This is part four in a series of posts on avoiding the axiom of choice (part one, part two, part three). In my previous post, we considered the “Axiom of Protoequivalence”—that is, the statement that every fully faithful, essentially surjective … Continue reading →

Posted in category theory, math, species | Tagged , , , , , , , , , , | 5 Comments

AC and equivalence of categories

Posted on June 5, 2014 by Brent

This is part three in a series of posts on avoiding the axiom of choice (part one, part two). In my previous post, I explained one place where the axiom of choice often shows up in category theory, namely, when … Continue reading →

Posted in category theory, math, species | Tagged , , , , , , , , , | 5 Comments

Unique isomorphism and generalized “the”

Posted on May 13, 2014 by Brent

This is part two in a series of posts on avoiding the axiom of choice; you can read part one here. In category theory, one is typically interested in specifying objects only up to unique isomorphism. In fact, definitions which … Continue reading →

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Avoiding the axiom of choice, part I

Posted on May 8, 2014 by Brent

I’m hard at work on my dissertation, and plan to get back to doing a bit of blogging based on stuff I’m writing and thinking about, as a way of forcing myself to explain things clearly and to potentially get … Continue reading →

Posted in category theory, math, species | Tagged , , , , , | 17 Comments