[I]n the chain of reactions accompanying the creative act, a link is missing. This gap which represents the inability of the artist to fully express his intention; this difference between what he intended to realise and did realise, is the personal "art coefficient" contained in the work.
In other words, the personal "art coefficient" is like an arithmetical relation between the unexpressed but intended and the unintentionally expressed."
In other words, a work of art is never what the artist fully intended. The difference between those two things - what he really wanted to create and what he in fact did create - is the personal "art coefficient".
RPG sessions are a bit like this, when you think about it. We are all nowadays, most of us, sandbox DMs, or non-railroading DMs, but still I think most DMs when planning a campaign have some ideas, however vague, about tone and quality and maybe certain key events and encounters. And this is also true on the microscale of individual aspects of a campaign, like NPCs, monsters and lairs: when planning or designing or thinking up such things, any DM has an idea in mind of how the PCs will interact with the NPC, defeat the monster, investigate the lair, etc.
We can therefore speak of such a thing as "the personal RPG coefficient". This is the difference between how the DM conceives of an in-game thing in the abstract, and how it actually turns out in practice. The clever and sarcastic NPC wizard does something stupid (the DM doesn't think things through). The sinister monster turns out to be really easy to defeat by the thoughtful players. The PCs discover the secret entrance to the lair before they come across the main entrance. And so forth.
Anybody who has DM'd a gaming session will be familiar with the personal RPG coefficient and its strange alchemy.
According to Duchamp the scale of the personal art coefficient didn't matter. All art is open to interpretation by the spectators. They are the ones who judge its success or failure. Not the artist. By implication, the artist may intend to do one thing, but utterly fail to achieve that in the final product. That doesn't matter, because those viewing it may judge it as good art and posterity may decide it is great art.
In the same way, it doesn't matter that the DM may have intended or predicted things will turn out one way, if they are different in the actual outcome. Those involved in the game may still judge it as good and fun.