Thanks for the feedback, abelian groups are a good example because so many groups are abelian (fields etc).
But, perhaps it's just getting late and the matters are now & the details are slipping my mind, but im starting to realize im unsure of many examples of file-like objects that aren't a file? The email where you responded re: packages was cut short, but it seemed to be that you were saying that record-types *aren't* file-like, when I had thought they are; I thought anything with simple means of serialization could be considered file-like, and that pseudofiles (/devs, /procs, etc) were also in the file-like category (which is apparently a misnomer on my part). Would anyone care to share an explanation of what is/is not a file-like object in Guix? Are fluids not considered file-like? I had thought that would be a use case where this geneticity becomes important. I remember when I first encountered gexps I thought, as FLOs didn't seem to be files, they were either records or fluids. It took me a good while to realize a file-like object is usually just a file, haha On Thu, Jun 16, 2022, 05:28 Maxime Devos <maximede...@telenet.be> wrote: > Blake Shaw schreef op wo 15-06-2022 om 21:40 [+0000]: > > On the contrary, lets say I'm writing an intro book on CT. If I'm > > demonstrating something trivial, say the initial object, I'm not > > going to refer to it as "an initial-like object" for the sake of > > generality. > > Neither does Guix? If you're in a context where only the basic object > (in this case, your demonstration the initial object) is used, just > talk about the basic object. But in a later section where you > generalize things to ‘initial-like objects’ (whatever that would be in > CT, I don't know any CT), you talk about ‘initial-like objects’, not > ‘initial object and initial-like objects’. > > For an example from another domain, consider groups in algebra. > In group theory, we have e.g. the fundamental theorem on homomorphisms. > Wikipedia formulates this as: > > Given two groups G and H and a group homomorphism f : G → H, let K be a > normal subgroup in G and φ the natural surjective homomorphism G → G/K > (where G/K is the quotient group of G by K). If K is a subset of ker(f) > then there exists a unique homomorphism h: G/K → H such that f = h∘φ. > > An equivalent statement could be made by replacing ‘given a group’ by > ‘given an Abelian group or a group’: > > Given two Abelian groups or groups G and H and a group homomorphism f : > G → H, let K be an Abelian normal subgroup or normal subgroup in G and > φ the natural surjective homomorphism G → G/K (where G/K is the > quotient group of G by K). If K is a subset of ker(f) then there exists > a unique homomorphism h: G/K → H such that f = h∘φ.’ > > But why do such a pointless thing, wouldn't just talking about groups > instead of ‘Abelian groups or groups’ be much simpler? > > TBC: here ‘file-like object’ ≃ ‘group’ and ‘file’ = ‘Abelian group’. > > Greetings, > Maxime. >
