Rózsa tokens interpreter


Rózsa Péter and recursive functions

Rózsa Péter sitting on a chair reading a book (date unknown)

Rózsa Péter (1905 – 1977) was a major contributor to computability theory. In 1934, ten years after the invention of primitive recursive functions, Péter set forth the formalization of these notions in a series of articles.

Even though the set of primitive recursive functions contains most of the functions usually found in science, one notable exception is the computable Ackermann–Péter function. It was Gödel who, in 1933, generalized primitive recursion to μ-recursive functions, which contain all computable functions.

Rózsa tokens

Dr Gregory Lafitte introduced Rózsa tokens as notation for μ-recursive functions.


This app was created by Mattéo Delabre, Guillaume Pérution-Kihli and Julien Rodriguez a way to increase awareness about Péter and Lafitte’s work, as a research tool for experimenting with tokens and as a proof that computers can simulate this computation model.

View presentation slides (French) »

Public project

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