The category of partitions with small blocks is a Banica-Speicher category of partitions inducing the corepresentation category of the bistochastic groups.
By the category of partitions with small blocks one denotes the subcategory of the category of all partitions whose underlying set is the set of all partitions with small blocks.
A partition is said to have small blocks if every block in is of size or .
The set of all pair partitions with small blocks is denoted by in [BanSp09].
The category of partitions with small blocks is the subcategory of generated by the set of partitions.
Via Tannaka-Krein duality for compact quantum groups, the category of all partitions with small blocks corresponds to the family of bistochastic groups.