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• CommentRowNumber1.
• CommentAuthormaxsnew
• CommentTimeSep 22nd 2017
• CommentRowNumber2.
• CommentAuthorTodd_Trimble
• CommentTimeSep 22nd 2017

What’s the explanation for the name?

• CommentRowNumber3.
• CommentAuthormaxsnew
• CommentTimeSep 22nd 2017

It’s computer science terminology. A thunk is a delayed computation and then you can force a delayed computation to actually run. Wikipedia has more: https://en.wikipedia.org/wiki/Thunk

• CommentRowNumber4.
• CommentAuthorMike Shulman
• CommentTimeSep 22nd 2017

What are $L$, $\theta$, and $\epsilon$ in the Kleisli category of a monad?

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeSep 23rd 2017

It’s computer science terminology. A thunk is a delayed computation and then you can force a delayed computation to actually run. Wikipedia has more: https://en.wikipedia.org/wiki/Thunk

This comment clearly deserves to be in the entry!

And I suggest to give these entries a “floating context TOC”. Of the ones we already have the most appropriate might be this:

  +-- {: .rightHandSide}
+-- {: .toc .clickDown tabindex="0"}
### Context
#### Constructivism, Realizability, Computability
+-- {: .hide}
[[!include constructivism - contents]]
=--
#### Category theory
+-- {: .hide}
[[!include category theory - contents]]
=--
=--
=--

• CommentRowNumber6.
• CommentAuthormaxsnew
• CommentTimeSep 23rd 2017
• (edited Sep 23rd 2017)

I’ve added an explicit description of the construction of a thunk-force category from a Kleisli category, and added a bit to the idea section about thunk and force.

Also, Urs I added the floating context but it doesn’t look quite right, compared to say Kleisli category. I fiddled with it a bit but couldn’t figure out the issue and I’m not very familiar with the markup language the nlab uses.

edit: I removed a paragraph in this comment that I realized was wrong so as not to mislead anyone

• CommentRowNumber7.
• CommentAuthorUrs
• CommentTimeSep 23rd 2017
• (edited Sep 23rd 2017)

Thanks!

The problem with the TOC code was just the whitespace you had in front of the lines, that must not be there, apparently. Now it works.

• CommentRowNumber8.
• CommentAuthormaxsnew
• CommentTimeSep 25th 2017

Added the inverse construction of thunk-force category to monad and included a characterization of what monads correspond to thunk-force categories.

• CommentRowNumber9.
• CommentAuthorMike Shulman
• CommentTimeSep 26th 2017

Interesting, thanks!

• CommentRowNumber10.
• CommentAuthorMike Shulman
• CommentTimeMay 13th 2020

Added “runnable monad” as the dual of a thunk-force category, corresponding to call-by-name.

• CommentRowNumber11.
• CommentAuthorMike Shulman
• CommentTimeMay 13th 2020

… but the changes don’t seem to have appeared. Are we in the middle of another editing bug? (I haven’t been reading the forum recently.)

• CommentRowNumber12.
• CommentAuthorMike Shulman
• CommentTimeMay 13th 2020

Fix the definition in terms of comonad and coalgebras.

• CommentRowNumber13.
• CommentAuthorMike Shulman
• CommentTimeMay 13th 2020

I guess you have to edit an extra time?

• CommentRowNumber14.
• CommentAuthorUrs
• CommentTimeMay 14th 2020

I know this (still) happens whenever one makes any edit to the redirects of a page: then none of the other edits will be rendered after submitting, only after one goes back and makes any further edit (while not changing the redirects again, I suppose)

• CommentRowNumber15.
• CommentAuthorMike Shulman
• CommentTimeMay 19th 2020

Suppose $(K,L,\theta,\epsilon)$ is a thunk-force category, and we have another functor $L':K\to K$ with a natural isomorphism $L\cong L'$. Can we transfer the thunk-force structure along this isomorphism to get a thunk-force structure $(K,L',\theta',\epsilon')$?

Similarly, can we transfer a thunk-force structure along equivalence of categories $K\simeq K'$?

1. Hi Urs, thanks for raising! Could you explain what precisely you mean by ’editing redirects of a page’? I don’t think I’ve come across this situation before, I will take a look once I understand the scenario.

• CommentRowNumber17.
• CommentAuthorMike Shulman
• CommentTimeMay 20th 2020

I think Urs means adding/removing lines of the form [[!redirects ...]].

• CommentRowNumber18.
• CommentAuthorUrs
• CommentTimeMay 20th 2020

Yes!

• CommentRowNumber19.
• CommentAuthorUrs
• CommentTimeMay 20th 2020
• (edited May 20th 2020)

Hm, I just tried to produce a minimal example of the bug on the Sandbox, but I failed to trigger the bug there.

On the other hand, I am encountering this bug every other day when editing pages, so I am sure it’s there. But apparently then some other factor is involved in triggering it.

2. Interesting. Please let me know the next time you encounter this, it should be fix-able, but without an example it is difficult for me to debug.

• CommentRowNumber21.
• CommentAuthorMike Shulman
• CommentTime7 days ago

Add DOIs for the citations. I glanced through the Hatcliff-Danvy paper and didn’t see anything that I recognized as related to this page. Presumably it is hidden in syntactic form somewhere?

• CommentRowNumber22.
• CommentAuthorUrs
• CommentTime1 day ago

I have now a “working” example of that bug to point to:

I have just started to add a new subsection to diffeological space. In the source code it’s visible as

  ### Relation to topological spaces


Then I added one redirect to the page

  [[!redirects D-topology]]


After that, the added material no longer appears in the output of the page.

$\,$

Experience shows that if next I made any other edit to the page the output will appear. But I’ll leave it as is for the moment in order to demonstrate the bug.

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