preorder As a command 8 categories below preorder Narrow by antisymmetric-relation 6 partial-order 5 weak-order 4 total-order 3 data-processing 1 event 1 process 1 symmetric-relation 1 partial-order 5total-order 3weak-order 4equivalence-relationinterval-orderlinear-extensiontopological-orderingwell-order