---
title: "Finite Combinatory Processes—Formulation I"
authors:
  - "Emil L. Post"
year: 1936
venue: "Journal of Symbolic Logic"
arxiv: null
doi: "10.2307/2268534"
source: "https://doi.org/10.2307/2268534"
topics:
  - post-machine
  - computability
  - tag-systems
  - post
seed_rank: 532
seed_batch: "foundations-greats-2026-08-13"
reviewed: "2026-08-13"
pool: "maths-foundations"
relevance_score: 10
lineage: foundations-of-computing
cites:
  - title: "On Computable Numbers, with an Application to the Entscheidungsproblem"
    url: "https://doi.org/10.1112/plms/s2-42.1.230"
    year: 1936
    arxiv: null
    doi: "10.1112/plms/s2-42.1.230"
  - title: "An Unsolvable Problem of Elementary Number Theory"
    url: "https://doi.org/10.2307/2371045"
    year: 1936
    arxiv: null
    doi: "10.2307/2371045"
  - title: "General recursive functions of natural numbers"
    url: "https://doi.org/10.1007/BF01565439"
    year: 1936
    arxiv: null
    doi: "10.1007/BF01565439"
  - title: "Formal reductions of the general combinatorial decision problem"
    url: "https://doi.org/10.2307/2371809"
    year: 1943
    arxiv: null
    doi: "10.2307/2371809"
see:
  - "515-on-computable-numbers-with-an-application-to-the-entscheidun"
  - "507-an-unsolvable-problem-of-elementary-number-theory"
  - "525-general-recursive-functions-of-natural-numbers"
  - "533-formal-reductions-of-the-general-combinatorial-decision-prob"
---

# Finite Combinatory Processes—Formulation I

## One-sentence takeaway

Post independently formulates computation as a worker following a finite list of instructions in a symbol space—the fourth 1936 model alongside Church, Turing, and Kleene.

## Why it matters here

Completeness of the 1936 moment: many formalisms, one effective calculability. Anoptic rewrite engines, production rules, and GRID COMMAND triggers sit closer to Post's "worker plus box of symbols" than to a Turing tape.

## Key ideas

- A *worker* applies a finite set of direction boxes to a two-way infinite sequence of marks, generating or erasing symbols according to the scanned box.
- Formulated independently of Turing and Church, and published in the same year.
- The process is the seed of Post's later tag systems, production systems, and the 1943 combinatorial reductions.
- Together with the other 1936 papers, makes "algorithm" look absolute rather than machine-specific.

## Caveats

## Links

- DOI: [10.2307/2268534](https://doi.org/10.2307/2268534)
- JSTOR: https://www.jstor.org/stable/2268534