On regular solutions of the generalized Dhombres equation

Verfasser / Beitragende:
[J. Smítal, M. Štefánková]
Ort, Verlag, Jahr:
2015
Enthalten in:
Aequationes mathematicae, 89/1(2015-02-01), 57-61
Format:
Artikel (online)
ID: 605508089
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024 7 0 |a 10.1007/s00010-014-0272-8  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00010-014-0272-8 
245 0 0 |a On regular solutions of the generalized Dhombres equation  |h [Elektronische Daten]  |c [J. Smítal, M. Štefánková] 
520 3 |a We consider continuous solutions $${f : \mathbb{R}_{+} \rightarrow \mathbb{R}_{+} = (0, \infty)}$$ f : R + → R + = ( 0 , ∞ ) of the functional equation $${f(xf(x)) = \varphi (f(x))}$$ f ( x f ( x ) ) = φ ( f ( x ) ) where $${\varphi}$$ φ is a given continuous map $${\mathbb{R}_{+} \rightarrow \mathbb{R}_{+}}$$ R + → R + . A solution f is singular if there are $${0 < a \leq b< \infty}$$ 0 < a ≤ b < ∞ such that $${f|_{(0,a)} > 1, f|_{[a,b]} \equiv 1}$$ f | ( 0 , a ) > 1 , f | [ a , b ] ≡ 1 , and $${f|_{(b,\infty)} < 1}$$ f | ( b , ∞ ) < 1 ; other solutions are regular. It is known that the range R f of a singular solution can contain periodic orbits of $${\varphi}$$ φ of all periods. In this paper we show that the range of a regular solution f contains no periodic point of $${\varphi}$$ φ of period different from $${2^n, n \in \mathbb{N}}$$ 2 n , n ∈ N so that $${\varphi|_{R_f}}$$ φ | R f has zero topological entropy. It follows, that the regular solutions are just the solutions f satisfying one of the conditions: (i) $${R_{f} \subseteq (0,1]}$$ R f ⊆ ( 0 , 1 ] , (ii) $${R_{f} \subseteq [1, \infty)}$$ R f ⊆ [ 1 , ∞ ) , (iii) there are $${0 1}$$ f | ( b , ∞ ) > 1 . 
540 |a Springer Basel, 2014 
690 7 |a Iterative functional equation  |2 nationallicence 
690 7 |a Invariant curves  |2 nationallicence 
690 7 |a Real solutions  |2 nationallicence 
690 7 |a Periodic orbits  |2 nationallicence 
700 1 |a Smítal  |D J.  |u Mathematical Institute, Silesian University, 746 01, Opava, Czech Republic  |4 aut 
700 1 |a Štefánková  |D M.  |u Mathematical Institute, Silesian University, 746 01, Opava, Czech Republic  |4 aut 
773 0 |t Aequationes mathematicae  |d Springer Basel  |g 89/1(2015-02-01), 57-61  |x 0001-9054  |q 89:1<57  |1 2015  |2 89  |o 10 
856 4 0 |u https://doi.org/10.1007/s00010-014-0272-8  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00010-014-0272-8  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Smítal  |D J.  |u Mathematical Institute, Silesian University, 746 01, Opava, Czech Republic  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Štefánková  |D M.  |u Mathematical Institute, Silesian University, 746 01, Opava, Czech Republic  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Aequationes mathematicae  |d Springer Basel  |g 89/1(2015-02-01), 57-61  |x 0001-9054  |q 89:1<57  |1 2015  |2 89  |o 10