Denote by $P^{I,y}_{x,w}$ be the parabolic Kazhdan-Lusztig polynomial of ${}^IW$ of type $y$.

I have heard that the polynomials $P^{I,q}_{x,w}$ give the transition matrix between a canonical basis and standard basis $\{T_w\}$ of $M^I$, where $M^I \cong \text{Ind}_{W_I}^W (\text{triv})$. Note that $T_s$ act as multiplication by $q$ on the trivial module.

My questions:

1. Is the above statement correct?

2. What is about the polynomials $P^{I,-1}_{x,w}$?

Denote by $P^{I,y}_{x,w}$ be the parabolic Kazhdan-Lusztig polynomial of ${}^IW$ of type $y$.

I have heard that the polynomials $P^{I,q}_{x,w}$ give the transition matrix between a canonical basis and standard basis $\{T_w\}$ of $M^I$, where $M^I \cong \text{Ind}_{W_I}^W (\text{triv})$. Note that $T_s$ act as multiplication by $q$ on the trivial module. See here.

My questions:

1. Is the above statement correct?

2. What is about the polynomials $P^{I,-1}_{x,w}$?