Set contains and object equal
68500
hashCode() for an array of objects for use in HashMap
99480
Why is predicate "all" as in all(SET) true if the SET is empty?
30955
Check if a string contains an element from a list (of strings)
148025
Is there an operator for 'contained in set or subset or subset of subset' and so on?
44160
Set theory: difference between belong/contained and includes/subset?
44858
JavaScript isset() equivalent
152371
equals vs Arrays.equals in Java
82315
is an empty set an element of {empty set}
75271
Equal, is equal to, equals, are equal to
125502
Empty set literal?
132692
Nonempty set mapped to $\emptyset$ and vice-versa
118824
What is the complement of empty set?
95798
Compare object instances for equality by their attributes
134644
Compare two objects with .equals() and == operator
123498
Is "empty set" an element of a set?
54497
Set Notation - Inclusion and Proper Inclusion
73313
Using contains() in LINQ to SQL