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Equation 3 · Part 1 · From n-Grams to Reasoning Models: A Technical History of the Language Model

Symbol n

nn
nn

What this part means

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

Its job in the formula

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

The passage around this formula

It has one fatal structural property. The number of possible contexts grows exponentially in n while the corpus does not, so almost every context of any useful length has been seen zero times. Maximum-likelihood counting assigns those contexts probability zero, and a single zero anywhere in a sentence sends the whole sequence probability to zero. The model is not merely uncertain about unseen material; it is confidently, catastrophically wrong about it.

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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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