It is very beautiful because it seems to match quite closesly the diagrammatic interpretation of a symmetric monoidal closed category. For example because of th

It is very beautiful because it seems to match quite closesly the diagrammatic interpretation of a symmetric monoidal closed category. For example because of the functoriality of the the monoidal tensor we have (g ∘ h) ⊗ (i ∘ j) = (g ∘ i) ⊗ (h ∘ j) so the two expressions should be indistinguishable. Indeed, in this Z syntax the expression k g h i j could be parsed either as k ( g(h) ⊗ i(j) ) or as k( (g⊗i)(h⊗j) ) but this ambiguity does not matter since they are equivalent. I wonder if k g h is a partial appilcation that would give you a function of the right type, i.e. the type of h ⊗ j. Anyway, beautiful stuff. PS. Not sure how to typeset this properly in this web site. PS. Thanks to commenter.