public override string ToString()
{
return($"{_lowerBound.Lower()}..{_upperBound.Upper()}");
}
/// <remarks>
/// <c>..</c> separator used instead of standard <c>,</c> in order to to avoid confusion with rational ranges.
/// <para><c>[ ]</c> used for closed bounds.</para>
/// <para><c>( )</c> used for open bounds, as it is more clear than inverted brackets <c>] [</c>.</para>
/// </remarks>
public override string ToString()
{
return(string.Format("{0}..{1}", _lowerBound.Lower(), _upperBound.Upper()));
}