[isabelle-dev] {..n} and {..<n}

Amine Chaieb ac638 at cam.ac.uk
Mon Mar 9 12:17:24 CET 2009

Is it about removing the {..n} completely or just for SUM?


Tobias Nipkow wrote:
> On nat, the sets {0..n} and {..n} are the same, which can be irksome.
> Hence I discourage the use of {..n}. However, there are notations such
> as "SUM k<=n. t" which stand for "setsum (%k. t) {..n}" and introduce
> {..n} by the backdoor.
> I am tempted to get rid of this and related notations and restrict to
> the canonical "SUM k=a..b. t".
> Would anybody miss the "k<=n" variant?
> Potential problem: for other types, eg int, k<=i cannot be replaced by
> some "k=a..i". But "SUM k<=i", "UN k<=i" over int (let alone real) seem
> unusual.
> Feelings?
> Tobias
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