## Properties Homology theories of directed spaces take values in directed algebraic structures such as abelian [[pogroup|pogroups]] and abelian [[pomonoid|pomonoids]]. ## Related entries * [[directed structure]] * [[pomonoid]] * [[directed homotopy theory]] ## References * Lauri Tart, subobject classification and geometric morphisms of partially ordered acts, masters thesis, [pdf](http://dspace.utlib.ee/dspace/bitstream/handle/10062/593/tart.pdf?sequence=5) * [[nLab:Marco Grandis]], [[nLab:directed algebraic topology]]