Consistent pricing process

A consistent pricing process (CPP) is any representation of (frictionless) "prices" of assets in a market. It is a stochastic process in a filtered probability space $(\Omega ,{\mathcal {F}},\{{\mathcal {F}}_{t}\}_{t=0}^{T},P)$ such that at time $t$ the $i^{th}$ component can be thought of as a price for the $i^{th}$ asset.

Mathematically, a CPP $Z=(Z_{t})_{t=0}^{T}$ in a market with d-assets is an adapted process in $\mathbb {R} ^{d}$ if Z is a martingale with respect to the physical probability measure $P$, and if $Z_{t}\in K_{t}^{+}\backslash \{0\}$ at all times $t$ such that $K_{t}$ is the solvency cone for the market at time $t$.

The CPP plays the role of an equivalent martingale measure in markets with transaction costs. In particular, there exists a 1-to-1 correspondence between the CPP $Z$ and the EMM $Q$.