public static NumeralWrapper Fibonacci(this NumeralWrapper numeral) => FixedPointCombinators <NumeralWrapper, NumeralWrapper> .Z(Fibonacci)(numeral);
 public static NumeralWrapper DivideBy(this NumeralWrapper dividend, NumeralWrapper divisor) =>
 FixedPointCombinators <NumeralWrapper, Func <NumeralWrapper, NumeralWrapper> > .Z(DivideBy)(dividend)(divisor);
 public static NumeralWrapper Factorial(this NumeralWrapper numeral) => FixedPointCombinators <NumeralWrapper, NumeralWrapper> .Z(Factorial)(numeral);