Dichotomy
（重定向自Dichotomic）
![In this image, the universal set U (the entire rectangle) is dichotomized into the two sets A (in pink) and its complement Ac (in grey).](/Images/godic/202501/08/Absolute_complement.svg4706.png")
A dichotomy is a partition of a whole (or a set) into two parts (subsets). In other words, this couple of parts must be
Such a partition is also frequently called a bipartition.
The two parts thus formed are complements. In logic, the partitions are opposites if there exists a proposition such that it holds over one and not the other.