Even when Twombly is not actually "dedicating" a work, when he is instead only idly doodling a name on his canvas--Leda, Mars, Bolsena--he is operating within the field of the performative: I mark you, I name you, I call you "painting." This is the big difference, the difference amounting to an absolute rupture of discursive intent, between the notion of the performative and that of analogy.
First, it is performative, suspending representation in favor of action: I mark you, I cance you, I dirty you.