• 検索結果がありません。

ALMOST PERIODIC MOTION IN COMPLETE SPACE

N/A
N/A
Protected

Academic year: 2022

シェア "ALMOST PERIODIC MOTION IN COMPLETE SPACE"

Copied!
2
0
0

読み込み中.... (全文を見る)

全文

(1)

Internat. J. Math. & Math. Sci.

Vol. 9 No. 3 (1986) 621-622

621

ALMOST PERIODIC MOTION IN COMPLETE SPACE

ANANT KUMAR

Satgharwa, P.O. Buniad Ganj

GAYA (INDIA), Pin-823003 (Received December 17.

1985)

ABSTRACT. It is interesting that in a complete space an almost periodic motion is periodic if the null set is closed and if is not closed then every point of its trajectory is a limit point.

KEY

WORDS AND PHRASES.

Compact, periodic and

almost

periodic

motions.

1980 AMS

SUBJECT CLASSIFICATION CODE.

34C35.

i. INTRODUCTION.

We studied "Poisson stable distal dynamical

systems"

in

Ill

where the word

"compact"

is missing from the statement and proof of theorem 2.7. It should be stated as theorem

3.1(below).

Now by means of this theorem we shall establish an interesting relation (theorem

3.2)

between almost periodic and periodic motions in a complete space X.

2. DEFINITIONS AND NOTATIONS.

We shall follow definitions and notations of [i].

3. MAIN RESULTS.

3.1 THEOREM. Compact almost periodic motion is Poisson stable and distal.

3.2 THEOREM. In a complete space X an almost periodic motion is periodic if the null set is closed in X and if is not closed then

y(x)

which is perfect and

x compact set.

PROOF. An almost periodic motion

(x,t)

is recurrent

[2,

theo 8.02 P.384] and if a recurrent motion is situated in a complete space then

cly(x)

is compact minimal [2, theo 7.07 P.377]. Therefore the motion

(x,t)

is compact. Hence

(x,t)

is compact almost periodic motion therefore it is Poisson stable and distal (3.1 above). Thus y(x) is closed and perfect set [, theo 2.1].

Now by [theo. VI.3 of 3,

P.87],

if x is not periodic then cl(cly(x)

y(x))

cly(x)

x

cl((x) (x)) (x)

x

cl

y(x)

if is closed set in X.

x

Which is impossible, as

xey(x)

and in case of a compact motion is also non-empty x

[3,

theo. II.8 P.20]. Therefore x is periodic. But if is not closed then

cl x) //.

x

3.3 COROLLARY. If in theorem 3.2,T=R (the set of reals) then y(x) is connected.

(2)

622

A. KUMAR

REFERENCES

i. PRASAD, S.S. and

KUMAR,

A.

"Stable

P and Distal Dynamical

Systems."

Internat. J.

Math. & Math. Sci. Vol. 7 No. (1984) 181-185.

2. NEMYTSKII,

V.V.

and STEPANOV, V.V.

"Qualitative Theory

of Differential

Equations",

University Press, 1960.

3. SELL, G.R.

"Topological Dynamics

and

Ordinary

Differential

Equations",

V.N.R.

Mathematical Studies 33

(1971).

参照

関連したドキュメント

Therefore f preserves any angle of the form mθ for positive integers m ≥ 1 and points at a distance θ on the great circle are mapped to some great circle.. We consider a

Abstract. This paper is an addendum to our earlier paper [8], where a sys- tematic study of quadratic systems of second order ordinary differential equa- tions defined in

We then show that a flow is cocyclic if and only if it is a filtered inverse limit of periodic flows (Theorem 4.9).. In Section 5, we define the

We call a topological space κ-compact if every subset of size κ has a complete accumulation point in it.. We show that if Φ(µ, κ, λ) holds and the space X is both µ-compact

A subset A of a space X is called an S-set in X [7] if every cover of A by regular closed subsets of X has a finite subcover, and called an rc-Lindel¨of set in X (resp., an almost

The simplest non-trivial division algebras that can be constructed over a rational function field in two variables are those that ramify along a divisor of degree three.. In this note

Some families of Merris graphs are found, including Kneser graphs K ( v, 2) and non-singular regular bipar- tite graphs.. For example, the Petersen graph and the Clebsch graph turn

The crucial facts are that a mild solution of the abstract Cauchy problem is asymptotically almost periodic in the Hille-Yosida space if and only if it is asymptotically almost