Equation 3 · Part 1 · Reliable AI Agents Are Control Systems, Not Chatbots

Symbol a_t

a_t

a_t

What this part means

the action.

Its job in the formula

$a_t$ is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Full expressionSymbol a_tArticle meaning

Where the article explains it

Let the environment have a latent state $s_t$ , expose an observation $o_t$ , and accept an action $a_t$ .

The passage around this formula

Let the environment have a latent state $s_t$ , expose an observation $o_t$ , and accept an action $a_t$ . The model and its surrounding prompt produce a policy

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

Open the illustrated subscripts: which member of a family? 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.