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DERIVATIVES OF A FUNCTION f

fʹ or df/dx	derivative of a function of a single real variable
∂if	partial derivative: ∂if = ∂f/∂xi
∂β f	derivative of order
β	positive multi-integer: β = (β₁,…, βd), βi ≥ 0
\|β\|	differentiability order: \|β\| = \|β₁1 + … \|βd\|
∂0f	derivative of order 0: ∂0 f = f
∇f	gradient: ∇f = (∂1f,…, ∂df)
df	differential
q	field: q = (q1,…,qd)
∇· q	divergence: ∇ · q = ∂₁q₁ + … ∂dqd
∇⁻¹q	primitive that depends continuously on q
q*	explicit primitive: q*(x) = f_{Γ(a, x)} q · dℓ