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Jan
26
answered Question about general comma categories
Jan
22
comment SupLat and InfLat
Yes, the "non obvious inclusion" is quite obvious to me. You can always compose a functor with an isomorphism (or some other functor) and get a new functor. I would not call this new functor an inclusion though, since it does not send an object to itself (CWM page 15). It is interesting to note that inclusion functor is an empty page in ncatlab. Anyway, thank you Zhen Lin, it does not seem that I missed anything subtle on this ncatlab page
Jan
22
comment SupLat and InfLat
Berci, I know, please look at the comments I wrote to Zhen Lin above
Jan
22
comment SupLat and InfLat
@ZhenLin However what I really found a bit puzzling was the sentence about inclusion functors. It seems (to me) to say that Suplat is included in a different way than InfLat into Pos. But this is obvious, since they are different categories, they are included with different functors. So why write this down? Or does this sentence mean something else subtly different?
Jan
22
comment SupLat and InfLat
It is not a contradiction, but isomorphism is much stronger than equivalence, so why not mention it?
Jan
21
comment SupLat and InfLat
thank you Berci. This is exactly what I thought. I am calling the ncatlab customer service...
Jan
21
accepted SupLat and InfLat
Jan
21
comment What is the “correct” way of making $\mathcal{P}(X)$ into a topological space?
I think your question/construction has to do with Alexandrov topology.
Jan
21
comment Relating categorical properties of arrows
ok! +1 . You can check also for epis and monos in ncatlab
Jan
21
comment Relating categorical properties of arrows
The title as it stands is not really meaningful. I would suggest something along the lines: "Relation between injections and monos".
Jan
21
comment Relating categorical properties of arrows
injection and surjection are not categorical afaik (they use elements of sets). they can be used in concrete categories though. The best/most general table I know is the one mentioned by Marco in his answer and found in the Joy of Cats. These implications are also implemented in the upcoming version of my WildCats package.
Jan
21
asked SupLat and InfLat
Jan
16
revised Demonstrate currying via homomorphism
edited small typos
Jan
16
comment Demonstrate currying via homomorphism
@HenningMakholm I fixed all typos
Jan
16
revised Demonstrate currying via homomorphism
edited small typos
Dec
27
awarded  Nice Question
Dec
24
comment A Tool to practice Categories / Allegories
@qartal yes, you have to type $BaseDirectory, or $UserBaseDirectory in Mathematica and see what folder location it gives back to you. Then place the package in that folder. These are standard operations for Mathematica users. Search the help file for $BaseDirectory to get more info.
Dec
20
answered A Tool to practice Categories / Allegories
Dec
20
comment A Tool to practice Categories / Allegories
I also do not understand. Please see my answer below.
Nov
21
comment Why is this not a category?
Indeed the claim is false. Does this category of monotone functions have a standard name?