Acceptable Unicode characters

Using Unicode seems to be irresistible. However, we must ensure avoiding problematic Unicode usage.

Below is a list of acceptable Unicode characters. All characters not listed below are forbidden. We forbid the use of accents (dot, hat, vec, etc.), because this can lead to visually ambiguous characters.

Acceptable lower-case Greek letters

α # (alpha)
β # (beta)
δ # (delta)
ϵ # (epsilon)
ε # (varepsilon)
γ # (gamma)
κ # (kappa)
λ # (lambda)
μ # (mu)
ν # (nu)
η # (eta)
ω # (omega)
π # (pi)
ρ # (rho)
σ # (sigma)
θ # (theta)
χ # (chi)
ξ # (xi)
ζ # (zeta)
ϕ # (psi)
φ # (varphi)

Acceptable upper-case Greek letters

Δ # (Delta)
∑ # (Sigma)
Γ # (Gamma)
Ω # (Omega)
Ψ # (Psi)
Φ # (Phi)

Acceptable mathematical symbols

∫ # (int)
∬ # (iint)
∭ # (iiint)
∞ # (infinity)
≈ # (approx)
∂ # (partial)
∇ # (nabla/del), note that nabla and del are indistinguishable
∀ # (forall)
≥ # (greater than equal to)
≤ # (less than equal to)