Equation 4 · Part 1 · Evaluating Trajectories, Not Answers
Symbol E
What this part means
The expected value operator: the probability-weighted average of the quantity inside its brackets.
Its job in the formula
E is part of the quantity the equation computes from the expression on the right.
Full expression→Symbol E→Article meaning
The passage around this formula
There is also a structural reason cost cannot be separated from reliability. If a run costs on average and succeeds with probability p , and the operator simply retries until success, the expected spend to first success is . which means a cheap unreliable agent and an expensive reliable one can occupy the same operating point. Reporting either number alone conceals which one you have bought. The honest artefact is a curve — quality against spend, produced by sweeping the effort level and the retry policy — rather than a point, and the honest comparison places two systems at matched spend and asks which reaches further.
Learn the underlying idea
Probability assigns a number from 0 to 1 to an event under a stated model. Zero means impossible within that model; one means certain.
Open the illustrated probability: a quantified chance guide →
See this notation across published equations →
Sources cited in the article section
These citations provide research context; check each source for the exact claim it supports.