namespace System
{
    [RequiresPreviewFeatures("Generic Math is in preview.", Url = "https://aka.ms/dotnet-warnings/generic-math-preview")]
    public interface ISignedNumber<TSelf> : IAdditionOperators<TSelf, TSelf, TSelf>, IAdditiveIdentity<TSelf, TSelf>, IComparable, IComparable<TSelf>, IComparisonOperators<TSelf, TSelf>, IDecrementOperators<TSelf>, IDivisionOperators<TSelf, TSelf, TSelf>, IEqualityOperators<TSelf, TSelf>, IEquatable<TSelf>, IFormattable, IIncrementOperators<TSelf>, IModulusOperators<TSelf, TSelf, TSelf>, IMultiplicativeIdentity<TSelf, TSelf>, IMultiplyOperators<TSelf, TSelf, TSelf>, INumber<TSelf>, IParseable<TSelf>, ISpanFormattable, ISpanParseable<TSelf>, ISubtractionOperators<TSelf, TSelf, TSelf>, IUnaryNegationOperators<TSelf, TSelf>, IUnaryPlusOperators<TSelf, TSelf>
        where TSelf, ISignedNumber<TSelf>!
    {
        static TSelf NegativeOne { get; }
    }
}