Multifractals

Defining f(α)

For each point (q, τ(q)) say the slope of the tangent line is . That is, α = -dτ/dq.
This tangent line passes through the point (q, τ(q)) and the point (0, y). Consequently,
-α = (y - τ(q))/(0 - q)
Solving for y,
y = q⋅α + τ(q)
Call this y-value f(α):
f(α) = q⋅α + τ(q)

Return to the range of α values.