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2 votes
1 answer
133 views

Definite description in homotopy type theory

I asked this question there and I have been suggested to ask it here. In a paper by David Corfield, we have an account of definite description in homotopy type theory. The author gives the following ...
Bruno's user avatar
  • 308
0 votes
2 answers
75 views

For every object, is there a unique notion of isomorphism?

Do you think that, according to most mathematicians, the following claim holds? (Claim) For every object, there is a unique notion of isomorphism. Perhaps one might think that for some sets, such as $(...
andpersand's user avatar
2 votes
1 answer
95 views

Is there a precise definition to "interpretation" in Mathematics?

A category (as distinguished from a metacategory) will mean any interpretation of the category axioms within set theory. Here are the details. Sect-2,page-10, Category Theory for the Working ...
Cathartic Encephalopathy's user avatar
1 vote
1 answer
207 views

Is the term "category" in Category theory entirely different from the category in topological spaces?

$(X, \tau) $ be a topological space. $A\subset X$ is said to be first category (meager) if it can be expressed as a countable union of nowhere dense sets. Otherwise we call the set $A$ second ...
Ussesjskskns's user avatar
2 votes
0 answers
75 views

Why do we care about non-equal but isomorphic objects in a category?

Note: this is more of a philosophical question. Said differently, what if we were to ask Categories to be extensional in the sense that if two objects are isomorphic then they are equal? Is there any ...
Julián's user avatar
  • 1,347
4 votes
1 answer
141 views

Is there a category (or rather a mathematical theory) for which we know a lot about, but not whether its object class is empty or not?

this is a bit of a vague question so let me describe a bit what motivates it: Yesterday I was reading the Wikipedia article about perfect numbers, where I find the section https://en.wikipedia.org/...
jgrk's user avatar
  • 117
3 votes
2 answers
300 views

Morphism composition is the property of morphism or the structure of category?

In the definition of category, there is a morphism composition law. If A, B, C are objects, and if f is a morphism from A to B, g is a morphism from B to C, then there is a corresponding morphism from ...
user32688's user avatar
  • 371
4 votes
1 answer
252 views

Reference request for subjective/objective logic for mathematicians

I am self-learning William Lawvere's Conceptual Mathematics and Sets For Mathematics. He mentioned subjective and objective logic. I really don't understand it. Do I have to read Hegel's to fully ...
Hamilton's user avatar
  • 602
0 votes
1 answer
150 views

Why do we *restrict* to universes instead of *surrounding* us with them?

In set theory and category theory one easily runs into the problem of size. For example Russell's paradox tells us that it is impossible to have consistent set theory allowing a set of all sets. ...
Jonas Linssen's user avatar
4 votes
0 answers
87 views

Non-associativeness of composition in deductive systems?

WARNING: The first three and last two paragraphs of this question concern historical/philosophical matters related to a secondary aim of the question. If you are more interested in the properly ...
Dry Bones's user avatar
  • 697
0 votes
0 answers
86 views

Why I should not study embedded categories?

In my lecture course of representation theory of $K$-algebras, we embedded the category of $A$-modules (where $A$ is an associative unital $K$-algebra) into the category of $K<X_i|i\in I>$-...
user avatar
14 votes
1 answer
2k views

Examples of co-implication (a.k.a co-exponential)

In Dual Intuitionistic Logic and a Variety of Negations: The Logic of Scientific Research Yaroslav Shramko, inspired by Popper, makes an interesting case that co-constructive logic as the logic of ...
Henry Story's user avatar
17 votes
6 answers
3k views

What exactly is an arrow in a category?

The usual definition of a category states: a category $\mathbf{C}$ consists of: A collection $\text{ob}(\mathbf{C})$ of objects A collection $\text{arr}(\mathbf{C})$ of arrows Some rules on the ...
augustoperez's user avatar
  • 3,226
1 vote
1 answer
179 views

How Topos "connect" continuous and discrete

I'm not a mathematician, but I have some knowledge in Category theory (mainly from computer science background). As I understand it, Topoi, and in particular presheaf category can "capture" the ...
kondor's user avatar
  • 159
2 votes
1 answer
118 views

Choice of closed monoidal structure

This might be a somewhat philosophical question in category theory. I sometimes have trouble understanding with some monoidal structures defined, why the one we choose are the "good ones". For example,...
Ludovic Monier's user avatar

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