Equation 3 · Part 1 · OpenAI Model Systems from First Principles: Weights, Post-Training, and Inference Compute
Symbol C_post
What this part means
post-training compute.
Its job in the formula
ost 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 C_post→Article meaning
Where the article explains it
where is pretraining compute, is post-training compute, Q is the number of served requests over the system’s life, and is the mean compute per request.
The passage around this formula
where is pretraining compute, is post-training compute, Q is the number of served requests over the system’s life, and is the mean compute per request. Until roughly 2024 the third term was treated as approximately fixed for a given model, and public discussion of capability collapsed onto the first. That assumption no longer holds. On current OpenAI models, is a parameter the caller sets: as verified on 8 August 2026, the model guidance documents a reasoninffort control taking the values none , low , medium , high , xhigh , and max , alongside a separate text.verbosity setting [ 2 ] .
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.
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Sources cited in the surrounding passage
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