Abstract Algebra: Theory and Applications · Problem 1.20

Preliminaries — Thomas Judson

Mathematics — Abstract Algebra · set-theory-operations

Problem

Let AA and BB be sets. Define the symmetric difference of AA and BB to be A△B=(A∖B)∪(B∖A)A \triangle B = (A \setminus B) \cup (B \setminus A). Prove the following statements. ((a)) A△B=(A∪B)∖(A∩B)A \triangle B = (A \cup B) \setminus (A \cap B); ((b)) A△B=B△AA \triangle B = B \triangle A; ((c)) (A△B)△C=A△(B△C)(A \triangle B) \triangle C = A \triangle (B \triangle C); ((d)) A△∅=AA \triangle \emptyset = A; ((e)) A△A=∅A \triangle A = \emptyset.

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