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# ?E in ?Sterm

E belongs to the set term Sterm.

?E
  A Prolog term.
?Sterm
  A set term.

## Description

This constraint states that E belongs to the set term Sterm. If E is not a known value the constraint is delayed. It is activated as soon as E becomes a known value. If Sterm is a ground set and E is known it checks if E belongs to Sterm.

### Fail Conditions

Fails if E cannot belong to Sterm.

### Resatisfiable

No.

## Examples

    [eclipse 4]: S `:: {}.. {1,2,3}, E in S.

    E = E
    S = S{{} .. {1, 2, 3}}

    Delayed goals:
            E in_s S{{} .. {1, 2, 3}}
    yes.

    [eclipse 5]: S `:: {}.. {1,2,3}, 1 in S.

    S = S{{1} .. {1, 2, 3}}
    yes.

## See Also

`:: / 2, notin / 2