| Title: | On a multiplicative type sum form functional equation and its role in information theory (English) | 
| Author: | Nath, Prem | 
| Author: | Singh, Dhiraj Kumar | 
| Language: | English | 
| Journal: | Applications of Mathematics | 
| ISSN: | 0862-7940 (print) | 
| ISSN: | 1572-9109 (online) | 
| Volume: | 51 | 
| Issue: | 5 | 
| Year: | 2006 | 
| Pages: | 495-516 | 
| Summary lang: | English | 
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| Category: | math | 
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| Summary: | In this paper, we obtain all possible general solutions of the sum form functional equations \[ \align \sum_{i=1}^{k}\sum_{j=1}^{\ell}f(p_iq_j)=&\sum_{i=1}^{k}g(p_i) \sum_{j=1}^{\ell}h(q_j)\\ \text{and} \sum_{i=1}^{k}\sum_{j=1}^{\ell}F(p_iq_j)=&\sum_{i=1}^{k} G(p_i)+\sum_{j=1}^{\ell}H(q_j)+ \lambda\sum_{i=1}^{k}G(p_i)\sum_{j=1}^{\ell}H(q_j) \endalign
\] valid for all complete probability distributions $(p_1,\ldots ,p_k)$, $(q_1,\ldots ,q_\ell )$, $k\ge 3$, $\ell \ge 3$ fixed integers; $\lambda \in \mathbb{R}$, $\lambda \ne 0$ and $F$, $G$, $H$, $f$, $g$, $h$  are real valued mappings each having the domain $I=[0,1]$, the unit closed interval. (English) | 
| Keyword: | sum form functional equation | 
| Keyword: | additive function | 
| Keyword: | multiplicative function | 
| MSC: | 39B22 | 
| MSC: | 39B52 | 
| MSC: | 39B82 | 
| MSC: | 94A15 | 
| idZBL: | Zbl 1164.39330 | 
| idMR: | MR2261636 | 
| DOI: | 10.1007/s10492-006-0018-6 | 
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| Date available: | 2009-09-22T18:27:04Z | 
| Last updated: | 2020-07-02 | 
| Stable URL: | http://hdl.handle.net/10338.dmlcz/134650 | 
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| Reference: | [1] J. Aczél, Z.  Daróczy: Charakterisierung der Entropien positiver Ordnung und der Shannonschen Entropie.Acta Math. Acad. Sci. Hungar. 14 (1963), 95–121. (German) MR 0191738, 10.1007/BF01901932 | 
| Reference: | [2] J. Aczél, Z.  Daróczy: On Measures of Information and Their Characterizations.Academic Press, New York-San Francisco-London, 1975. MR 0689178 | 
| Reference: | [3] M. Behara, P.  Nath: Additive and non-additive entropies of finite measurable partitions.Probab. Inform. Theory  II. Lect. Notes Math. Vol.  296, Springer-Verlag, Berlin-Heidelberg-New York, 1973, pp. 102–138. MR 0379019 | 
| Reference: | [4] T. W. Chaundy, J. B.  Mcleod: On a functional equation.Edinburgh Math. Notes 43 (1960), 7–8. MR 0151748, 10.1017/S0950184300003244 | 
| Reference: | [5] Z. Daróczy: On the measurable solutions of a functional equation.Acta Math. Acad. Sci. Hungar. 22 (1971), 11–14. MR 0293280, 10.1007/BF01895986 | 
| Reference: | [6] Z. Daróczy, A.  Jarai: On the measurable solutions of functional equation arising in information theory.Acta Math. Acad. Sci. Hungar. 34 (1979), 105–116. MR 0546725, 10.1007/BF01902599 | 
| Reference: | [7] Z. Daróczy, L.  Losonczi: Über die Erweiterung der auf einer Punktmenge additiven Funktionen.Publ. Math. 14 (1967), 239–245. (German) MR 0240492 | 
| Reference: | [8] K. K. Gulati: Some functional equations connected with entropy.Bull. Calcutta Math. Soc. 80 (1988), 96–100. Zbl 0654.39004, MR 0956797 | 
| Reference: | [9] J. Havrda, F.  Charvát: Quantification method of classification process. Concept of structural $\alpha $-entropy.Kybernetika 3 (1967), 30–35. MR 0209067 | 
| Reference: | [10] Pl. Kannappan: On some functional equations from additive and nonadditive measures  I.Proc. Edinb. Math. Soc., II. Sér. 23 (1980), 145–150. MR 0597119, 10.1017/S0013091500003023 | 
| Reference: | [11] Pl. Kannappan: On a generalization of some measures in information theory.Glas. Mat., III. Sér. 9 (1974), 81–93. Zbl 0287.39006, MR 0363671 | 
| Reference: | [12] L. Losonczi: A characterization of entropies of degree  $\alpha $.Metrika 28 (1981), 237–244. Zbl 0469.94005, MR 0642931, 10.1007/BF01902897 | 
| Reference: | [13] L. Losonczi: Functional equations of sum form.Publ. Math. 32 (1985), 57–71. Zbl 0588.39005, MR 0810591 | 
| Reference: | [14] L. Losonczi, Gy.  Maksa: On some functional equations of the information theory.Acta Math. Acad. Sci. Hungar. 39 (1982), 73–82. MR 0653676, 10.1007/BF01895217 | 
| Reference: | [15] Gy. Maksa: On the bounded solutions of a functional equation.Acta Math. Acad. Sci. Hungar. 37 (1981), 445–450. Zbl 0472.39003, MR 0619897, 10.1007/BF01895147 | 
| Reference: | [16] D. P. Mittal: On continuous solutions of a functional equation.Metrika 23 (1976), 31–40. Zbl 0333.39006, MR 0415111, 10.1007/BF01902848 | 
| Reference: | [17] C. E. Shannon: A mathematical theory of communication.Bell Syst. Tech. Jour. 27 (1948), 378–423, 623–656. Zbl 1154.94303, MR 0026286 | 
| Reference: | [18] I. Vajda: Bounds on the minimal error probability on checking a finite or countable number of hypotheses.Probl. Inf. Transm. 4 (1968), 9–19. MR 0267685 | 
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