Googology Wiki
Googology Wiki
Not to be confused with OCF.

δOCF is a googological system introduced by a Japanese Googologist Jason,[1][2][3] and is the first system defined by shifting definition. It was used to create a large number グラハム数〜legend of δ〜 submitted to a Japanese googology event as a variant of Graham's number, but was rejected by a referee because of the incompleteness of the definition.[4] Namely, it is currently ill-defined.

It is intended to perform as an ordinal function associated to an OCF through the method. Although it is currently ill-defined, it is expected to be a powerful function which goes beyond many other OCFs if it will be appropriately formalised. Since it is quite complicated for others to understand from the explanation of its intended behaviour, Jason created δφ as a simpler ordinal function without using an OCF.


  1. The user page of Jason in Japanese Googology Wiki.
  2. Jason, δ関数の展開ルール, Google Drive.
  3. Jason, δ解説 もっと詳しく, Google Document.
  4. Jason, グラハム数〜legend of δ〜, twiiter.

See also

By Aeton: Okojo numbers · N-growing hierarchy
By 新井 (Arai): Arai's \(\psi\)
By バシク (BashicuHyudora): Primitive sequence number · Pair sequence number · Bashicu matrix system 1/2/3/4
By ふぃっしゅ (Fish): Fish numbers (Fish number 1 · Fish number 2 · Fish number 3 · Fish number 4 · Fish number 5 · Fish number 6 · Fish number 7 · S map · SS map · s(n) map · m(n) map · m(m,n) map) · Bashicu matrix system 1/2/3/4 computation programmes · TR function (I0 function)
By じぇいそん (Jason): Irrational arrow notation · δOCF · δφ · ε function
By 甘露東風 (Kanrokoti): KumaKuma ψ function
By 小林銅蟲 (Kobayashi Doom): Sushi Kokuu Hen
By koteitan: Bashicu matrix system 2.3
By mrna: 段階配列表記 · 降下段階配列表記 · 多変数段階配列表記 · SSAN · S-σ
By Naruyoko Naruyo: Y sequence computation programme · ω-Y sequence computation programme
By Nayuta Ito: N primitive · Flan numbers · Large Number Lying on the Boundary of the Rule of Touhou Large Number 4
By p進大好きbot: Large Number Garden Number
By たろう (Taro): Taro's multivariable Ackermann function
By ゆきと (Yukito): Hyper primitive sequence system · Y sequence · YY sequence · Y function · ω-Y sequence
See also: Template:Googology in Asia