■
Frobenius-Perron operator
- on measures
- on densities
if is nonsingular w.r.t. and is a.c.w.r.t. with density ,
absolutely continuous (measure)
を上の有限な測度とする.から が出る時,
はに関して絶対連続といい, と表す.
反対の概念は,特異 (singular) singular (measure)
, となる時,はに関して特異であると言う.
nonsingular (transformation)
Hunt_OnTheApproximationThe map is sait to be nonsingular with respect to a measure
if ならば が必ず成立
ergodic
is ergodic with respect to a measure if ならば もしくは = 0 が必ず成立
Mane_ErgodicTheoryAndDifferentiableDynamicsgiven a measure-preserving map of a space .
Maps which satisfy the following condition are called ergodic.
There exist no set such that and .ロビンソン_力学系
写像 がそれによって不変な測度 に関してエルゴード的であるとは,
なる の任意の不変可測集合 について,
となることをいう.
つまり,上のergodic mapに対しては,
すべての不変可測集合はにおいて測度0かまたは全測度をもつかのどちらかである.
reducible
Hunt_OnTheApproximationA map is reducible if there exists a nontrivial negatively invariant subset of .
By nontrivial set we mean nonempty subset that is -measurable, where is a probability measure, with .
If no such set exists, is said to be irreducible.
- irreducible と ergodicとの差は,
か, かどうか.
- If is irreducible, then it is also ergodic.
quasicompact operator
reflexive space
BV space
conservative
未: is conservative with respect to negatively invariant
Hunt_OnTheApproximationA measurable subset is sait to be negatively invariant if