The set of two-colored partitions forms a strict involutive monoidal category via the operations of composition, tensor product and involution.
Given two-colored partitions the pairing is called composable if the upper row of and the lower row of agree in size and coloring.
If is composable, if for every we denote the lower row of by and the upper row by , if we identify and with each other and if
is the join of the partitions induced by on and by on , then the composition of is given by the two-colored partition with lower row , with upper row , with blocks
and with the coloring of on and that of on .
If are two-colored partitions, if for every we denote the lower row and its total order of by and, likewise, the upper row by and if we denote the coloring of by , then tensor product of is given by the two-colored partition satisfying the following conditions:
For any two-colored partition , if we denote by the lower row and by the upper row of , by the blocks of and by the coloring of , then the involution of is given by the partition whose lower row is , whose upper row is , whose blocks are and whose coloring is .