# Comparison with action calculi

This style of semantics is most similar to Milner's action calculi, except that in this presentation control edges are used to control order of evaluation, where in Milner's presentation, evaluation is delayed by placing sub-graphs inside controls, for example (using slightly different notation):

'hello' |
'world' |

There is a trade-off here between categorical simplicity (monoidal categories v. premonoidal pre-2-cagegories) and graphical simplicity (control edges v. controls containing sub-graphs).