A binary relation which kinda orders things, but is not a
partial order,
total order, or
complete order.
A quasi-ordering is reflexive and transitive, but not necessarily complete.
The relation R is a quasi-ordering if for x, y, and z:
- xRx, yRy,zRz
- (xRy) & (yRz) => (xRz)
- However, it is not necessarily so that xRy or yRx, etc.