Before you can read the parent note, you need to be fluent in the little pieces of notation it throws around: x, y, H, Mi, R, argmin, E, L, sup, ϵ, and a handful of words like "recursive", "amplify", "judge". This page builds each one from nothing, in an order where every symbol is earned before it is used.
Everything in this topic is a conversation between three kinds of things. Figure s01 (below) draws them: a blue question card on the left, a yellow model box in the middle, a pink answer card on the right — read it left-to-right as "question goes in, answer comes out."
Why the topic needs this. Scalable oversight is entirely about the gap between "producing y" (easy for a strong AI) and "checking y is good" (hard for a weak human). You cannot talk about that gap without names for the question and the answer.
Here is the idea the whole field pivots on: we treat a human judgement as a machine too.Figure s02 (below) shows it: two inputs feed a yellow "H" box — the pink answer y from the top, the blue question x from the bottom — and out comes a score on the right.
Why the bar ∣ matters. An answer is only good relative to a question. "42" is a great answer to "6×7" and a terrible answer to "capital of France". The ∣ says: always judge the answer in the light of its question. You will meet this exact bar again in the recursive formula, where a second thing gets added after it.
Why the topic needs H. Scalable oversight's whole worry is: what happens when H can no longer tell good from bad by itself? Naming the human as H lets us write, precisely, the moment H breaks — and the fix.
An AI cannot be trained on the word "good." It needs a number to chase. That number is the reward.
Why the topic needs R. This is the bridge to RLHF (Reinforcement Learning from Human Feedback), the standard method the parent note is upgrading. In RLHF, R comes straight from H. Scalable oversight's central move is to change what feeds into R — that is literally the whole "recursive reward" idea.
Before we can read the training formula, we need the word that appears inside it. It is really a picture, so we draw it first. Figure s04 (below) shows the whole move: one hard yellow task on the left is chopped into blue pieces, each piece is solved into a pink partial answer, and the pieces are glued back into one answer on the right.
The training formula uses three more compact symbols. They look scary; each is one plain sentence.
Figure s03 (below) nails the min-vs-argmin distinction that trips everyone up: the pink dot marks the value at the bottom (that is min), while the yellow arrow points along the ground at the model that sits there (that is argmin).
Now we can read the topic's key formula, because we already know every piece — including the two-argument reading M(x,y) ("review this answer") from Section 1.
Here P(⋯) is a probability — a number between 0 (never) and 1 (always) measuring how often something happens.
Reveal each line only after answering it in your head.
What does (x,y) stand for?
The question card x and the answer card y — one problem, one proposed answer.
What is the difference between M(x) and M(x,y)?
M(x) = "solve this question"; M(x,y) = "review this already-written answer" (produces a critique, not a fresh answer).
What does the subscript in M2 mean?
A generation label ("second model"), NOT an exponent.
How do you read the bar in H(y∣x)?
"the quality of answer ygiven question x" — always judge the answer in light of its question.
What does R do, and why do we need it?
Turns a judgement into a number to train on; the AI climbs toward high R.
What does Amplify(M,x) mean?
The strong answer you get by decomposing x, solving the pieces with M, and gluing them back (human orchestrates).
What single change turns standard reward into recursive reward?
Adding Mi−1(x,y) after the given-bar — an AI assistant reviews the answer to help the human judge.
What does argminM return?
The modelM that makes the following quantity smallest (the argument, not the value).
What does Ex[⋅] mean?
The average of the bracketed quantity over all questions x.
What does L(a,b) measure?
How much a and b disagree — zero when identical, larger when they differ.
What is ϵ used for?
To say "the failure chance is smaller than any tiny number you pick."
In debate, what are J and {+1,−1}?
The human judge and its two allowed verdicts (for-side wins / against-side wins).
In one sentence, what is the core idea of the whole topic?
Judge work you cannot do by splitting it into small pieces you can judge, recursively.
Recall Self-test: rebuild the recursive reward from memory
Start from Rstandard(x,y)=H(y∣x), then add the previous model's help behind the bar: Rrecursive(i)(x,y)=H(y∣x,Mi−1(x,y)). If you can explain why the extra term goes after the bar (it is context the human is "given"), you are ready for the parent note.