Monotonicity of inverse Kazhdan-Lusztig polynomials

For arbitrary Coxeter systems, we prove that inverse Kazhdan-Lusztig polynomials satisfy a monotonicity property. This follows from the validity of Soergel’s conjecture and the existence of injective morphisms between Rouquier complexes in the mixed perverse Hecke category. The monotonicity property is generalised to parabolic Kazhdan-Lusztig polynomials.