using System;

using System.Collections.Generic;

​

public class Test {

    public string Name { get; set; }

    public Test(string name) {

        Name = name;

    }

}

public class Program

{

    public static void Main()

    {

        List<Test> l1 = new List<Test>();

        l1.Add(new Test("Peter")); l1.Add(new Test("Klaus"));

        List<Test> l2 = new List<Test>();

        l2.Add(new Test("Peter")); l2.Add(new Test("Franz"));

        List<Test> l3 = new List<Test>();

        l2.Add(new Test("Josef")); l2.Add(new Test("Fritz"));

        Console.WriteLine("Do l1 and l2 have an element in common:");

        Console.WriteLine(

            l1.Exists(a => l2.Exists(b => a.Name == b.Name))

        );

        Console.WriteLine("Do l1 and l3 have an element in common:");

        Console.WriteLine(

            l1.Exists(a => l3.Exists(b => a.Name == b.Name))

        );

​

    }

}