Assuming a contiguous subset of Nat

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Y2i

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Nov 22, 2015, 10:32:12 AM11/22/15
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I wanted to express an assumption that my set Ver is a subset of Nat and is contiguous.  It seems it can be done using a Max() operator, like below:

(* A singleton set with a maximal element from S or empty set *)

Max(S) == { i \in S : \A j \in S : i >= j }


ASSUME /\ Ver \subseteq Nat \* Ver is a subset of Nat

       /\ \A i \in Ver : i + 1 \notin Ver => Max(Ver) = { i } \* Ver is contiguous


Is there a better/cleaner way to express this assumption?


Thank you,

Yuri


Stephan Merz

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Nov 22, 2015, 10:50:43 AM11/22/15
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How about

  \E m,n \in Nat : Ver = (m .. n)

Regards,
Stephan

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Y2i

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Nov 22, 2015, 12:31:30 PM11/22/15
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This is much better, thank you Stephan!
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