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Equation 4 · Part 8 · The Hardest Unsolved Problems in Multimodal AI

subscript

Ntok=HP⋅WP,N_{\mathrm{tok}} = \frac{H}{P} \cdot \frac{W}{P},
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

There is a structural reason this compounds rather than merely adding up, and it is worth making explicit because it exposes an assumption rather than a vague sense of difficulty. A vision transformer front end tokenises an image of height H and width W at patch size P into NtokN_{\mathrm{tok}} = HP\frac{H}{P} ⋅\cdot WP\frac{W}{P}, and a video of T sampled frames multiplies that by T again. Any fixed context budget therefore forces a three-way trade between spatial patch size, temporal sampling rate, and clip duration — coarsen the patches, subsample frames, or truncate the clip. Whichever is chosen, information is discarded before a language model ever sees a token, and the TemporalBench failure…

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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 →

Sources cited in the article section

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