Equation 2 · Part 1 · The Hardest Unsolved Problems in AI Agent Architecture
Symbol T
What this part means
the when.
Its job in the formula
T is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol T→Article meaning
Where the article explains it
When T is small and rewards are dense, that crude attribution washes out quickly.
The passage around this formula
Read the inner sum literally: every action in the trajectory is credited with everything that happens from that point on, not with its own specific contribution. When T is small and rewards are dense, that crude attribution washes out quickly. When T is large and the reward is a single terminal signal — a multi-step coding task that either compiles and passes its tests or does not, a multi-turn support conversation that either resolves the case or does not — the…
Learn the underlying idea
A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.
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Sources cited in the article section
- [2] ArCHer: Training Language Model Agents via Hierarchical Multi-Turn RL ↗
- [3] Reflexion: Language Agents with Verbal Reinforcement Learning ↗
These citations provide research context; check each source for the exact claim it supports.