← All parts of this equation

Equation 51 · Part 2 · A Reference Frame Becomes Classical by Publishing Its Orientation

Symbol pi

ϵ=π\epsilon=\pi
π\pi

What this part means

the values from zero to.

Its job in the formula

pi is an input to the expression that computes the quantity on the left.

Where the article explains it

(Tr⁡(R1TR2)−12)\left(\frac{\operatorname{Tr}(R_1^{\mathsf T}R_2)-1}{2}\right), with values from zero to π\pi .

The passage around this formula

This expression follows from the Haar distribution of rotation angle, whose density on [0,π\pi] is 2sin⁡2(θ/2)\sin^2(\theta/2)/π\pi . It passes the limiting checks: at ϵ\epsilon=0 , blind success is zero; at ϵ\epsilon=π\pi , it is one. The redundancy definition is informative only when 1-δ\delta>pblind(ϵ)p_{\mathrm{blind}}(\epsilon) . Otherwise an empty box can qualify as a witness.

Read this part in the article →

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.

Open the illustrated variables: a letter stands for a value guide →

See this notation across published equations →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.