Commodity := iota.
Res := Commodity list of actor.

Commutation ::=
    Inititor, alium (actor.)
    Quid, quo (commodity.)

A commutation of own's quid and their quo :=
    Own, their := actor.
    Quid, quo := commodity.

    (Own is this.)
    (Own is not their.)
    (Res of own contains quid.)
    (Res of their contains quo.)

    -> Commutation of
        Own initiator
        Their alium
        Quid, quo

Quis, quid pro quo? :=
    Sum := this.
    Quis := actor.
    Quid, quo := commodity.

    -> a commutation of sum quid and quis quo.
        
Accept deal! :=
    deal := commutation.

    (This is commutation's alium.)
    Deal quid, deal quo = deal quo, deal quid!