Answer
Lacan was a French psychoanalyst who developed his own theory of psychoanalysis, called Lacanian psychoanalysis. Lacan used formulae from predicate logic and topology to augment his work. He believed that these formulae could help to explain the unconscious mind and the workings of psychoanalysis. Lacan's work has been controversial, but it has also been influential in the development of psychoanalysis and other fields of psychology.