Any and All Puzzle

AnyAndAll.cs

using static System.Console;
using System.Collections.Generic;
using System.Linq;

namespace AnyAndAll
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var sequence = GetSpecialSequence();

            // Prints "True"
            WriteLine(sequence.All(b => b == true)); 

            // Prints "False"
            WriteLine(sequence.Any(b => b == true));
        }

        private static IEnumerable<bool> GetSpecialSequence()
        {
            // Puzzle: What should this implementation be?
            return null;
        }
    }
}

Your function can return a simple empty instance.

return new List∆bool∆();

private static IEnumerable<bool> GetSpecialSequence() => Enumerable.Empty<bool>();

My buddy once said: 'All of my purses are coach purses.' His statement was vacuously true because he owns no purses at all (or at least that's what he wants me to believe.)

var ownedPurses = Enumerable.Empty<Purse>();
Func<Purse, bool> isCoachPurse = purse => purse is CoachPurse;

Console.WriteLine(ownedPurses.All(isCoachPurse)); // all of the purses ARE coach purses
Console.WriteLine(!ownedPurses.Any(purse => !isCoachPurse(purse))); // none of the purses are NOT coach purses