Symbol in context

$s^2$

This entry links every published equation using this exact notation. Its meaning may change between equations.

Meanings in context

Article-grounded definition

the square of s; the scale.

ds^2 = -U(Z)^2\,dx_0^2 + dZ^2 + dx^2 + dy^2, \qquad x_0 := ct, \qquad U(Z) := 1 + \frac{gZ}{c^2}.

This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.

ds^2 = -U(\mathbf x)^2\,dx_0^2 + \delta_{ij}\,dx^i dx^j

This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.

\mathbb{E}\!\left[(x - \hat{x})^2\right] \approx \frac{s^2}{12}

This equation gives an approximation: it relates the quantities while allowing an approximation.