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Equation 4 · Part 2 · The Hardest Unsolved Problems in Multimodal AI

Symbol H

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

What this part means

the height.

Its job in the formula

H occurs above the fraction bar. The numerator is divided by the entire denominator below it.

Where the article explains it

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.

The passage around this formula

…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,…

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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

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