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Difference between revisions of "Non-oscillation interval"

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''interval of disconjugacy''
 
''interval of disconjugacy''
  
A connected interval <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672201.png" /> on the real axis <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672202.png" /> such that any non-trivial solution <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672203.png" /> of a given ordinary linear differential equation of order <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672204.png" /> with real coefficients,
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A connected interval $  J $
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on the real axis $  \mathbf R $
 +
such that any non-trivial solution $  x = x ( t) $
 +
of a given ordinary linear differential equation of order n $
 +
with real coefficients,
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672205.png" /></td> <td valign="top" style="width:5%;text-align:right;">(*)</td></tr></table>
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$$ \tag{* }
 +
x  ^ {(} n) + a _ {1} ( t) x  ^ {(} n- 1) + \dots + a _ {n} ( t) x
 +
=  0 ,
 +
$$
  
has on it more than <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672206.png" /> zeros, an <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672207.png" />-fold zero counted <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672208.png" /> times. Properties of solutions of (*) on a non-oscillation interval have been well studied (see, for example, [[#References|[1]]]–[[#References|[3]]]). There are several generalizations of the concept of a non-oscillation interval, to linear systems of differential equations, to non-linear differential equations, and also to other types of equations (difference, with deviating argument).
+
has on it more than n- 1 $
 +
zeros, an $  m $-
 +
fold zero counted $  m $
 +
times. Properties of solutions of (*) on a non-oscillation interval have been well studied (see, for example, [[#References|[1]]]–[[#References|[3]]]). There are several generalizations of the concept of a non-oscillation interval, to linear systems of differential equations, to non-linear differential equations, and also to other types of equations (difference, with deviating argument).
  
 
====References====
 
====References====
 
<table><TR><TD valign="top">[1]</TD> <TD valign="top">  P. Hartman,  "Ordinary differential equations" , Birkhäuser  (1982)</TD></TR><TR><TD valign="top">[2]</TD> <TD valign="top">  A.Yu. Levin,  "Non-oscillation of solutions of the equation <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672209.png" />"  ''Russian Math. Surveys'' , '''24''' :  2  (1969)  pp. 43–99  ''Uspekhi Mat. Nauk'' , '''24''' :  2  (1969)  pp. 43–96</TD></TR><TR><TD valign="top">[3]</TD> <TD valign="top">  W.A. Coppel,  "Disconjugacy" , Springer  (1971)</TD></TR></table>
 
<table><TR><TD valign="top">[1]</TD> <TD valign="top">  P. Hartman,  "Ordinary differential equations" , Birkhäuser  (1982)</TD></TR><TR><TD valign="top">[2]</TD> <TD valign="top">  A.Yu. Levin,  "Non-oscillation of solutions of the equation <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n067/n067220/n0672209.png" />"  ''Russian Math. Surveys'' , '''24''' :  2  (1969)  pp. 43–99  ''Uspekhi Mat. Nauk'' , '''24''' :  2  (1969)  pp. 43–96</TD></TR><TR><TD valign="top">[3]</TD> <TD valign="top">  W.A. Coppel,  "Disconjugacy" , Springer  (1971)</TD></TR></table>

Latest revision as of 08:03, 6 June 2020


interval of disconjugacy

A connected interval $ J $ on the real axis $ \mathbf R $ such that any non-trivial solution $ x = x ( t) $ of a given ordinary linear differential equation of order $ n $ with real coefficients,

$$ \tag{* } x ^ {(} n) + a _ {1} ( t) x ^ {(} n- 1) + \dots + a _ {n} ( t) x = 0 , $$

has on it more than $ n- 1 $ zeros, an $ m $- fold zero counted $ m $ times. Properties of solutions of (*) on a non-oscillation interval have been well studied (see, for example, [1][3]). There are several generalizations of the concept of a non-oscillation interval, to linear systems of differential equations, to non-linear differential equations, and also to other types of equations (difference, with deviating argument).

References

[1] P. Hartman, "Ordinary differential equations" , Birkhäuser (1982)
[2] A.Yu. Levin, "Non-oscillation of solutions of the equation " Russian Math. Surveys , 24 : 2 (1969) pp. 43–99 Uspekhi Mat. Nauk , 24 : 2 (1969) pp. 43–96
[3] W.A. Coppel, "Disconjugacy" , Springer (1971)
How to Cite This Entry:
Non-oscillation interval. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Non-oscillation_interval&oldid=17615
This article was adapted from an original article by Yu.V. Komlenko (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article