{Directed, Undirected} x {Biased, Unbiased}

reference
    '(Co)relational computing in Catlab: The operad of UWDs and its algebras, Evan Patterson, MIT Categories Seminar, December 2020'
img-20250819221853075

Reference: (Co)relational computing in Catlab: The operad of UWDs and its algebras, Evan Patterson, MIT Categories Seminar, December 2020