noun
reflexive partial order
Technical term in mathematics (order theory). A partial order that is reflexive, i.e., every element is related to itself.
反射的半順序は、反射律、反対称律、推移律を満たす二項関係である。
A reflexive partial order is a binary relation satisfying reflexivity, antisymmetry, and transitivity.
半順序 (partial order) is the broader term; 反射的半順序 explicitly includes reflexivity, which is often assumed in standard partial orders.
Compound of 反射的 (reflexive) + 半順序 (partial order), a direct calque of the English mathematical term.