The matheme (from Greek: μάθημα "lesson") is a concept introduced in the work of the 20th century French psychoanalyst Jacques Lacan.
The term matheme "occurred for the first time in the lecture Lacan delivered on November 4th, 1971 [...] Between 1972 and 1973 he gave several definitions of it, passing from the use of the singular to the use of the plural and back again".
They were intended to introduce some degree of technical rigour in philosophical and psychological writing, replacing the often hard-to-understand verbal descriptions with formulae resembling those used in the hard sciences, and as an easy way to hold, remember, and rehearse some of the core ideas of both Freud and Lacan.
Though sometimes disparaged as a case of "physics envy" or accused of introducing false rigor into a discipline that is more literary theory than hard science, there is also something of a sense of humor in Lacan's formulas: of one 'sigla which I have introduced in the form of an algorithm', Lacan himself has declared that 'it is created to allow for a hundred and one different readings, a multiplicity that is admissible as long as the spoken remains caught in its algebra'.
[4] Serge Leclaire, who is one of the most respected and distinguished of all French analysts, remarked in 1975, for example, that whilst the mathemes might have a certain pedagogic utility, they were basically no more than "graffiti"'.