1. Introduction
General Markov chain only has locally strong Markov property, which is the main obstruction to solve the pro- blem of Markov chain constructing [1] [2] . The papers construct a strong Markov chain corresponding to its transition function using Ray-Knight compact method [3] [4] , which is named regular chain. The papers give an orbit construction of birth and death process [5] [6] . The papers solve the construction problem of two-sided birth and death process [3] -[11] . The papers prove that the appended points in the compacting and the points on the Martin entrance boundary are monogamy, under the condition of finite entrance boundary [12] -[14] . This paper makes a strong Markov process by Ray-Knight compacting, discusses its orbit nature and explains the significance probability of Kolmogorov forward and backward equations.
2. The Orbit Natures of Regular Chain
Assume
is a honest transition function on
,
is its density func-
tion,
is its resolvent,
is the Ray-Knight compacting of
,
and
is the Ray re-
solvent and the semi-group correspondence, denote
as non-ramification point set,
,
, then E is Borel algebras on
,
is the
regular chain of correspondence to
. Denote
and 
respectively as escape time and return time, by Blumenthal 0 - 1 law, for arbitrary
,
or 1,
or 1, if
, x is called absorption state, if
,
is called sojourn state, if
,
is called regular state, if
,
is called temporary state.
Theorem 1 Let
, then
(1)
is a regular state,
(2) on
, the distribution of escape time
is the exponential distribution of
,
(3) on
,
and
is mutual independent.
(4) if
, for arbitrary
,
.
Proof (1) Assume
is not a regular state, then
. for arbitrary
, it is easy to check
, and when
,
, thus
,
this is a contradictory proposition.
(2) The proof is same as Theorem
5 in
[15] .
(3) If
or
, then
or
, the conclusion is true, if
, for arbitrary Borel subset
and
,
![]()
Let
, we have
.
then, on
,
,
and
is mutual independent.
(4) If
, for arbitrary
, According to the strong Markov properties of
and (3), we can obtain that
![]()
Give arbitrary
, and continuous function
on
with
,
![]()
but
, in addition,
![]()
thus,
.
Remark 1 (3), (4) in the Theorem 1 are equivalence with the Theorem
6 in
[15] , but it require
, do not incloude
.
Remark 2 According to (2) in Theorem 1,
is a temporary state, if and only if
is a sojourn state of
the regular chain
.
Definition 1 Let
is the constant set of
, the interval in
is called i-interval of ![]()
Theorem 2 If
, then for arbitrary
, we can get a stopping time squence
, with
, when
, we have
, when
, we have
. And for arbitrary
,
![]()
For arbitrary
, denote
as the number of
belong to
, we have
.
Proof Let
,
, ,
where
are the stoping time of
. for arbitrary
, if
, since
is right continuity,
, and
![]()
then we have almost sure
on
.
Since
is strong Markov chain, and for arbitrary
,
![]()
then we have almost sure
on
.
For arbitrary
, obviously
, by Theorem
3.1 in
[15]
![]()
According to Fatou lemma, for arbitrary
,
, then almost sure there are only finite
in a finite interval, such that
, this means
.
Theorem 3 If
, then
(1) Almost sure,
do not contain any interval,
(2) Almost sure,
is a dense set in itself.
Proof (1) Obviously,
is a optional set, denote
(where we assume
), then
is a monotone increasing left continuous process, and adapt in
, denote
, thus
is a optional right continuous process. Let
,
It is easy to check that
, thus
is a optional set adapt in
.
Assume
is debut time, If
, by Section Theorem, exists a stopping time
in
, such that
, and
on
, by (2) in the theorem 1,
![]()
this is a contradictory proposition, thus
and almost sure
do not contain any interval.
(2) The proof is similar to (1).
3. The Significance Probability of Kolmogorov Equations
Theorem 4 For arbitrary
,
and ![]()
, (1)
if and only if
.
Proof For arbitrary
,
![]()
![]()
then (1) and the following equation is equivalence.
(2)
According to Theorem 1, we have
![]()
and the necessary and sufficient condition of equality is
.
For arbitrary
let
is the first k i-interval of
,
![]()
Corollary 1 The following conditions are equivalence [16] [17] .
(1) The backward equation of Kolmogorov is true,
(2) For arbitrary
,
(3) Density matrix
is conservative,
(4) Almost sure, for all
and
, we have
.
Theorem 5 For arbitrary ![]()
(3)
if and only if for all
-interval
almost sure
.
Proof (1) Asumme
,
![]()
![]()
Obviously
are not intersection. It is easy to check if there are infinite
to make
,
then
, and if
, then existing
, when
, we have
, thus that
, and
![]()
(2) For arbitrary
, by (1),
(4)
and the necessary and sufficient condition of equality is
.
Thus we get the equation
, (5)
let
go to
in Equation (5), we can obtain Equation (3).
Corollary 2 The Kolmogorov forward equations are true if and only if for all
and i-interval
, almost sure
.
Remark 3 Equation(3) is equivalent to
. (6)
Remark 4 If
contains some transient state, then Equation (1) is true if and only if
![]()
Remark 5 Under the condition of
, Equation (1) is not probably true. for the example
in Remark 1, the Ray-Knight compaction of
under the resolvent
is
, thus, the corresponding
regular chain meets the equation
, but according to Corollary 2, Doob process does not
satisfy Kolmogorov forward equation, then
also does not satisfy forward equation.
If
is an non-honest transition function with total stability, then we can construct a
honest transition function
on
such that
, (7)
where the density matrix of
is
such that
(8)
the resolvent of
is
, then
(9)
Assume
is a regular chain corresponding to
. For
, by Theorem 1,
is a absorption state, this is ![]()
Set
, obviously
is a killing Markov process, for arbitrary ![]()
, and
, we known the transition function
of
is
.
For arbitrary
, since
then for arbitrary
the following equations are Equivalence.
![]()
It is easy to get:
Proposition 1 Assume
is an non-honest transition function with total stability,
is corresponding Markov process with killing, then
satisfy Kolmogorov backward equation if and only if almost sure for all
and
,
.
Proposition 2 Assume
is an non-honest transition function with total stability,
is corresponding Markov process with killing, then
satisfy Kolmogorov forward equation if and only if almost sure for all
and
,
.