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Equation 7 · Part 8 · The Real Economics of Shipping a Model to a Device

subscript

Qdistill∗=Cdistillcteacher−cstudent.Q^{*}_{\mathrm{distill}} = \frac{C_{\mathrm{distill}}}{c_{\mathrm{teacher}} - c_{\mathrm{student}}}.
subscript

What this part means

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

Its job in the formula

A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.

The passage around this formula

Here CdistillC_{\mathrm{distill}} is the one-time training cost, Q is the number of queries served over the deployment’s life, and cstudentc_{\mathrm{student}} and cteacherc_{\mathrm{teacher}} are the marginal cost per query of serving each model, wherever that serving happens. The break-even query volume is Qdistill∗=Cdistillcteacher−cstudentQ^{*}_{\mathrm{distill}} = \frac{C_{\mathrm{distill}}}{c_{\mathrm{teacher}} - c_{\mathrm{student}}}. As a worked illustration only, not a claim about any real company’s ledger: take Alpaca’s disclosed $600 and assume, as an order-of-magnitude figure consistent with how frontier and compact API tiers are typically priced relative to each other, that a teacher-class model costs $0.002 per query to serve and a well-distilled student costs $0.0002 — a tenfold gap. Then Qdistill∗Q^{*}_{\mathrm{distill}}…

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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.

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Sources cited in the surrounding passage

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