CHAP 2

• A set is a well-defined collection, list or group of distinct objects or symbols. It is usually denoted by a capital letter of the English alphabet.
• An element is an object or a symbol which belongs to a set and is denoted by the symbol €.
• The cardinality of a set A is the number of elements of a set A denoted by n(A), read as "the cardinality of A".
• An empty set is a set which has no element and is denoted by {}
• A set is finite if it is empty or the elements in the set can be counted and the counting process must come to an end.
• A set is infinite if it is not finite
• A universal set is the set containing all the elements of the sets under discussion and is denoted by U.
• A Venn diagram is a pictorial representation of relationships between sets.
• Tabular or Listing Method - Using this method, we actually list down or enumerate the members of a set. The elements of the set are separated by commas and are enclosed with braces.
• 2. Defining Property Method - This is a method of describing a set using the properties of characteristics of the elements of the set.
• Equal sets are two or more sets having the same elements,regardless of order in which the elements are written.
• Equivalent sets are two or more finite sets having the same cardinality
• Joint sets are two or more sets having at least one common element.
• Disjoint sets are two or more sets having no common elements
• The union of two sets A and B, denoted by A U B, is the set of elements that belong to A or to B or to both
• The intersection of two sets A and B, denoted by A n B, is the set containing all the common elements of sets A and B.
• If A is a subset of U, then the complement of set A denoted by A' is the set whose elements are all the elements of U which do not belong to A