added to the entry (here) a few lines with a tad more details

]]>I have added pointer to:

- J. K. Vizzotto, Thorsten Altenkirch, A. Sabry,
*Structuring quantum effects: superoperators as arrows*, Mathematical Structures in Computer Science**16**3 (2006) 453-468 [arXiv:quant-ph/0501151, doi:10.1017/S0960129506005287]

What I was looking for is the answer to the following question:

In a compact closed category, “superoperators”

$\big(\mathscr{H} \multimap \mathscr{H}\big) \longrightarrow \big(\mathscr{K} \multimap \mathscr{K}\big)$hence

$\mathscr{H} \otimes \mathscr{H}^\ast \longrightarrow \mathscr{K} \otimes \mathscr{K}^\ast$may equivalently be understood as

$\mathscr{H} \otimes \mathscr{K} \longrightarrow \mathscr{H} \otimes \mathscr{K}$and then be composed as such. Is there a standard name for this re-identification and/or the resulting notion of composition of superoperators?

]]>brief entry *superoperator*, just for completeness