Dear all,

While porting some of my theories to the current development version, I've just noticed that the renaming of sublisteq to subseq done by Manuel in May (639eb3617a86) has one bad effect:


The name subseq is already used in Topological_Spaces to formalise the concept of a subsequence. This name is now hidden by the definition in Sublist, in particular when I import HOL-Probability.

Can this name clash be eliminated before the next release such that I don't have to write Topological_Spaces.subseq everywhere?

Thanks,
Andreas

On 26/05/17 08:16, Tobias Nipkow wrote:
Thank you for your research. I am perfectly happy with "sublist" (for the contiguous case) and "subseq" (for the general case) and think we should adopt it.

[Then we would rename sublisteq -> subseq and sublist :: "'a list ⇒ nat set ⇒ 'a list" (in List) to something else, eg sublist_index)

Tobias

On 25/05/2017 21:13, Jasmin Blanchette wrote:

On 25.05.2017, at 20:41, Tobias Nipkow <nip...@in.tum.de> wrote:

I don't think that sublist, subsequence and substring really have much of a bias in either direction, except possibly substring, but the latter does indeed sound too specialized.

Wikipedia has a clear bias (and I did not edit it, nor did I look it up before writing my previous email):

    https://en.wikipedia.org/wiki/Subsequence
    https://en.wikipedia.org/wiki/Substring

Popular algorithm sbooks like Cormen et al. follow the same definition of subsequence. Standard expressions like "longest increasing subsequence" depend on this semantics.

As for sublist, all the examples I see by Googling either "sublist", "is_sublist", "isSublist", or "indexOfSubList" in Java, Python, Scala, etc., have the contiguous semantics. Including this page:

    http://www4.in.tum.de/lehre/praktika/psv/psv98/Vorlesung5/aufg4.html

I'm not saying we should rename the Isabelle concepts, just that Isabelle is the odd (wo)man out.

Jasmin


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