What is a Cartel?
Jacques Lacan invented the "cartel" in 1964 as one of the three pillars of psychoanalysis most aligned with the transmission of psychoanalytic teaching. It consists of work with three people, plus one, who have each oriented themselves toward the production of "bits of [psychoanalytic] knowledge" in transference to the School. It is open to any one and every one.
It does not pretend to eradicate the place of power but effects a separation through knowledge. The "plus one" is not a place of representation, neither a comrade nor a schoolmaster, but a function of "hystericization" aimed at disrupting the hierarchical and fraternal group effects. The cartel, as a fundamental organ of the psychoanalytic school, sends each one back to their loneliness in relation to the psychoanalytic cause.
Jacques-Alain Miller says that:
The plus-one must come with question marks [...] and make holes in heads. This implies that he refuses to be a master who puts to work; to be the one who knows; to be an analyst in the cartel; and this in order to be that agent provocateur from where there is a teaching.
More about the "cartel" can be read here.