Before revision: When the value of refractive index of the e-ray (nₑ) is larger than the index of refraction index of the o-ray(n₀), the material is Positive uniaxialmaterial .
After revision: When the value of refractive index of the e-ray (nₑ) is larger than the index of refraction index of the o-ray(n₀), the material is positive uniaxialthe .