Definition:Ruelle-Perron-Frobenius Operator/One-Sided Shift Space of Finite Type

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Let $\struct {X_\mathbf A ^+, \sigma}$ be a one-sided shift of finite type.

Let $\map C {X _\mathbf A ^+, \C}$ be the continuous mapping space.

Let $F_\theta^+$ be the space of Lipschitz functions on $X_\mathbf A ^+$.

Let $B$ be either $\map C {X _\mathbf A ^+, \C}$ or $F_\theta^+$.

Let $f \in B$.

The Ruelle-Perron-Frobenius operator $\LL_f : B \to B$ is defined as:

$\ds \forall g \in B : \map {\paren {\LL_f g} } x := \sum_{y \mathop \in \map {\sigma^{-1} } x} e^{\map f y} \map g y$

where $\map {\sigma^{-1} } x$ denotes the preimage of $x$ under $\sigma$:

$\map {\sigma^{-1} } x = \set {\sequence {i, x_0, x_1, \ldots} : \map {\mathbf A} {i, x_0} = 1}$

Also known as

This is also called:

the transfer operator
the Ruelle operator.

Also see

Source of Name

This entry was named for David Pierre RuelleOskar Perron and Ferdinand Georg Frobenius.