Keten Çopur, Ayşegül; Hacıoğlu, Emirhan; Gürsoy, Faik New insights on a pair of quasi-contractive operators in Banach spaces: results on Jungck type iteration algorithms and proposed open problems. (English) Zbl 07764079 Math. Comput. Simul. 215, 476-497 (2024). MSC: 47J25 47H09 00A27 PDFBibTeX XMLCite \textit{A. Keten Çopur} et al., Math. Comput. Simul. 215, 476--497 (2024; Zbl 07764079) Full Text: DOI
Akewe, H.; Mogbademu, A. A.; Olaoluwa, H. O. Fixed point theorems and equivalence results for classes of multivalued mappings in modular function spaces. (English) Zbl 1509.47098 Acta Univ. Sapientiae, Math. 14, No. 1, 1-22 (2022). MSC: 47J26 47H04 PDFBibTeX XMLCite \textit{H. Akewe} et al., Acta Univ. Sapientiae, Math. 14, No. 1, 1--22 (2022; Zbl 1509.47098) Full Text: DOI
Doğan, Kadri; Gürsoy, Faik; Karakaya, Vatan; Khan, Safeer Hussain Some new results on convergence, stability and data dependence in \(n\)-normed spaces. (English) Zbl 1493.47111 Commun. Fac. Sci. Univ. Ank., Sér. A1, Math. Stat. 69, No. 1, 112-122 (2020). MSC: 47J26 47H09 PDFBibTeX XMLCite \textit{K. Doğan} et al., Commun. Fac. Sci. Univ. Ank., Sér. A1, Math. Stat. 69, No. 1, 112--122 (2020; Zbl 1493.47111) Full Text: DOI
Okeke, Godwin Amechi; Khan, Safeer Hussain Approximation of fixed point of multivalued \(\rho\)-quasi-contractive mappings in modular function spaces. (English) Zbl 1483.47115 Arab J. Math. Sci. 26, No. 1-2, 75-93 (2020). MSC: 47J26 47H04 47H09 PDFBibTeX XMLCite \textit{G. A. Okeke} and \textit{S. H. Khan}, Arab J. Math. Sci. 26, No. 1--2, 75--93 (2020; Zbl 1483.47115) Full Text: DOI
Rezapour, Shahram; Yao, Jen-Chih; Zakeri, Seyyed Hasan A strong convergence theorem for quasi-contractive mappings and inverse strongly monotone mappings. (English) Zbl 1460.47033 Pure Appl. Funct. Anal. 5, No. 3, 733-746 (2020). MSC: 47J25 47H05 47H09 47J20 47H10 PDFBibTeX XMLCite \textit{S. Rezapour} et al., Pure Appl. Funct. Anal. 5, No. 3, 733--746 (2020; Zbl 1460.47033) Full Text: Link
Akhtar, Zahid; Khan, Muhammad Aqeel Ahmed Rates of convergence for a class of generalized quasi contractive mappings in Kohlenbach hyperbolic spaces. (English) Zbl 1498.54041 Sci. Bull., Ser. A, Appl. Math. Phys., Politeh. Univ. Buchar. 81, No. 1, 173-182 (2019). MSC: 54H25 54E40 47H09 PDFBibTeX XMLCite \textit{Z. Akhtar} and \textit{M. A. A. Khan}, Sci. Bull., Ser. A, Appl. Math. Phys., Politeh. Univ. Buchar. 81, No. 1, 173--182 (2019; Zbl 1498.54041) Full Text: arXiv
Ayari, M. Iadh; Jaradat, M. M. M.; Mustafa, Z. A best proximity point theorem for special generalized proximal \(\beta \)-quasi contractive mappings. (English) Zbl 1488.54104 Fixed Point Theory Appl. 2019, Paper No. 17, 10 p. (2019). MSC: 54H25 54E40 PDFBibTeX XMLCite \textit{M. I. Ayari} et al., Fixed Point Theory Appl. 2019, Paper No. 17, 10 p. (2019; Zbl 1488.54104) Full Text: DOI
Ayari, Mohamed Iadh; Mustafa, Zead; Jaradat, Mohammed Mahmoud Generalization of best proximity points theorem for non-self proximal contractions of first kind. (English) Zbl 1462.54043 Fixed Point Theory Appl. 2019, Paper No. 7, 10 p. (2019). MSC: 54H25 54E40 PDFBibTeX XMLCite \textit{M. I. Ayari} et al., Fixed Point Theory Appl. 2019, Paper No. 7, 10 p. (2019; Zbl 1462.54043) Full Text: DOI
Fathollahi, Shahin; Rezapour, Shahram Efficacy of coefficients on rate of convergence of some iteration methods for quasi-contractions. (English) Zbl 1397.47016 Iran. J. Sci. Technol., Trans. A, Sci. 42, No. 3, 1517-1523 (2018). MSC: 47J25 47H09 65J15 PDFBibTeX XMLCite \textit{S. Fathollahi} and \textit{S. Rezapour}, Iran. J. Sci. Technol., Trans. A, Sci. 42, No. 3, 1517--1523 (2018; Zbl 1397.47016) Full Text: DOI
Ayari, Mohamed Iadh Best proximity point theorems for generalized \(\alpha\)-\(\beta\)-proximal quasi-contractive mappings. (English) Zbl 1474.54116 Fixed Point Theory Appl. 2017, Paper No. 16, 13 p. (2017). MSC: 54H25 54E40 PDFBibTeX XMLCite \textit{M. I. Ayari}, Fixed Point Theory Appl. 2017, Paper No. 16, 13 p. (2017; Zbl 1474.54116) Full Text: DOI
Chauhan, Surjeet Singh; Utreja, Kiran; Imdad, Mohammad; Ahmadullah, Md. Strong convergence theorems for a quasi contractive type mapping employing a new iterative scheme with an application. (English) Zbl 1370.47059 Honam Math. J. 39, No. 1, 1-25 (2017). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{S. S. Chauhan} et al., Honam Math. J. 39, No. 1, 1--25 (2017; Zbl 1370.47059) Full Text: DOI
Wang, Xuewu Strong convergence of iterative sequences for asymptotically \(\phi\)-hemi quasi-contractive operators. (Chinese. English summary) Zbl 1363.47122 Math. Appl. 29, No. 2, 269-273 (2016). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{X. Wang}, Math. Appl. 29, No. 2, 269--273 (2016; Zbl 1363.47122)
Razani, A.; Goodarzi, Z. Iteration by Cesàro means for quasi-contractive mappings. (English) Zbl 1466.47057 Filomat 28, No. 8, 1575-1584 (2014). MSC: 47J26 47H09 47H25 PDFBibTeX XMLCite \textit{A. Razani} and \textit{Z. Goodarzi}, Filomat 28, No. 8, 1575--1584 (2014; Zbl 1466.47057) Full Text: DOI
Kim, Jong Kyu; Dashputre, Samir; Hyun, Ho Geun Convergence theorems of \(S\)-iteration process for quasi-contractive mappings in Banach spaces. (English) Zbl 1315.47066 Commun. Appl. Nonlinear Anal. 21, No. 4, 89-99 (2014). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{J. K. Kim} et al., Commun. Appl. Nonlinear Anal. 21, No. 4, 89--99 (2014; Zbl 1315.47066)
Khan, Safeer Hussain; Fukhar-ud-din, H. Common fixed points of finite families of quasi-contractive type operators in normed spaces. (English) Zbl 1475.47091 Proceedings of the 2nd annual international conference on computational mathematics, computational geometry and statistics, CMCGS 2013, Singapore, February 4–5, 2013. Singapore: Global Science and Technology Forum (GSTF). 71-74 (2013). MSC: 47J26 47H09 PDFBibTeX XMLCite \textit{S. H. Khan} and \textit{H. Fukhar-ud-din}, in: Proceedings of the 2nd annual international conference on computational mathematics, computational geometry and statistics, CMCGS 2013, Singapore, February 4--5, 2013. Singapore: Global Science and Technology Forum (GSTF). 71--74 (2013; Zbl 1475.47091)
Alotaibi, Abdullah; Kumar, Vivek; Hussain, Nawab Convergence comparison and stability of Jungck-Kirk-type algorithms for common fixed point problems. (English) Zbl 1476.47088 Fixed Point Theory Appl. 2013, Paper No. 173, 30 p. (2013). MSC: 47J26 47H09 PDFBibTeX XMLCite \textit{A. Alotaibi} et al., Fixed Point Theory Appl. 2013, Paper No. 173, 30 p. (2013; Zbl 1476.47088) Full Text: DOI
Shi, Lu; Xu, Shaoyuan Common fixed point theorems for two weakly compatible self-mappings in cone \(b\)-metric spaces. (English) Zbl 1429.54059 Fixed Point Theory Appl. 2013, Paper No. 120, 11 p. (2013). MSC: 54H25 54E40 PDFBibTeX XMLCite \textit{L. Shi} and \textit{S. Xu}, Fixed Point Theory Appl. 2013, Paper No. 120, 11 p. (2013; Zbl 1429.54059) Full Text: DOI
Reich, Simeon; Zaslavski, Alexander J. Generic contractivity for a class of nonlinear mappings. (English) Zbl 1300.47062 Lib. Math. (N.S.) 33, No. 1, 15-20 (2013). MSC: 47H09 47H10 54E50 54E52 PDFBibTeX XMLCite \textit{S. Reich} and \textit{A. J. Zaslavski}, Lib. Math. (N.S.) 33, No. 1, 15--20 (2013; Zbl 1300.47062) Full Text: DOI
Kumar, Vivek; Latif, Abdul; Rafiq, Arif; Hussain, Nawab \(S\)-iteration process for quasi-contractive mappings. (English) Zbl 1455.47023 J. Inequal. Appl. 2013, Paper No. 206, 15 p. (2013). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{V. Kumar} et al., J. Inequal. Appl. 2013, Paper No. 206, 15 p. (2013; Zbl 1455.47023) Full Text: DOI
Akbulut, Sezgin; Özdemir, Murat Picard iteration converges faster than Noor iteration for a class of quasi-contractive operators. (English) Zbl 1295.47071 Chiang Mai J. Sci. 39, No. 4, 688-692 (2012). MSC: 47J25 65J15 47H09 PDFBibTeX XMLCite \textit{S. Akbulut} and \textit{M. Özdemir}, Chiang Mai J. Sci. 39, No. 4, 688--692 (2012; Zbl 1295.47071)
Hussain, Nawab; Chugh, Renu; Kumar, Vivek; Rafiq, Arif On the rate of convergence of Kirk-type iterative schemes. (English) Zbl 1325.47120 J. Appl. Math. 2012, Article ID 526503, 22 p. (2012). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{N. Hussain} et al., J. Appl. Math. 2012, Article ID 526503, 22 p. (2012; Zbl 1325.47120) Full Text: DOI
Khan, Safeer Hussain Common fixed points of quasi-contractive type operators by a generalized iterative process. (English) Zbl 1519.47107 IAENG, Int. J. Appl. Math. 41, No. 3, 260-264 (2011). MSC: 47J26 47H09 PDFBibTeX XMLCite \textit{S. H. Khan}, IAENG, Int. J. Appl. Math. 41, No. 3, 260--264 (2011; Zbl 1519.47107) Full Text: Link
Zhang, Xian Fixed point theorem of generalized quasi-contractive mapping in cone metric space. (English) Zbl 1231.65101 Comput. Math. Appl. 62, No. 4, 1627-1633 (2011). MSC: 65J15 47H10 47H09 PDFBibTeX XMLCite \textit{X. Zhang}, Comput. Math. Appl. 62, No. 4, 1627--1633 (2011; Zbl 1231.65101) Full Text: DOI
Liu, Zeqing; Ume, Jeong Sheok Convergence and stability of the Ishikawa iteration schemes for quasi-contractive mappings in uniformly convex Banach spaces. (English) Zbl 1218.47108 Int. J. Pure Appl. Math. 66, No. 1, 11-24 (2011). MSC: 47J25 47H10 47H09 PDFBibTeX XMLCite \textit{Z. Liu} and \textit{J. S. Ume}, Int. J. Pure Appl. Math. 66, No. 1, 11--24 (2011; Zbl 1218.47108)
Shao, Ying; Zheng, Xiaodi; Zhang, Shuyi Some strong convergence theorems for two contractive mappings. (Chinese. English summary) Zbl 1368.47085 J. Nanyang Norm. Univ. 8, No. 6, 9-12 (2009). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{Y. Shao} et al., J. Nanyang Norm. Univ. 8, No. 6, 9--12 (2009; Zbl 1368.47085)
Yildirim, İsa; Özdemir, Murat; Kiziltunç, Hükmi On the convergence of a new two-step iteration in the class of quasi-contractive operators. (English) Zbl 1236.47081 Int. J. Math. Anal., Ruse 3, No. 37-40, 1881-1892 (2009). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{İ. Yildirim} et al., Int. J. Math. Anal., Ruse 3, No. 37--40, 1881--1892 (2009; Zbl 1236.47081) Full Text: Link
Wei, Xing; Zhang, Wanxiong A fixed point theorem for quasi-contractive mappings in partially ordered sets with applications. (Chinese. English summary) Zbl 1212.47042 J. Sichuan Norm. Univ., Nat. Sci. 32, No. 4, 421-423 (2009). MSC: 47H10 47H09 PDFBibTeX XMLCite \textit{X. Wei} and \textit{W. Zhang}, J. Sichuan Norm. Univ., Nat. Sci. 32, No. 4, 421--423 (2009; Zbl 1212.47042)
Khan, S. H. Common fixed points of two quasi-contractive operators in normed spaces by iteration. (English) Zbl 1228.47060 Int. J. Math. Anal., Ruse 3, No. 1-4, 145-151 (2009). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{S. H. Khan}, Int. J. Math. Anal., Ruse 3, No. 1--4, 145--151 (2009; Zbl 1228.47060) Full Text: Link
Saeidi, Shahram Existence of ergodic retractions for semigroups in Banach spaces. (English) Zbl 1166.47055 Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 69, No. 10, 3417-3422 (2008). Reviewer: Jarosław Górnicki (Rzeszów) MSC: 47H20 47H09 47H10 PDFBibTeX XMLCite \textit{S. Saeidi}, Nonlinear Anal., Theory Methods Appl., Ser. A, Theory Methods 69, No. 10, 3417--3422 (2008; Zbl 1166.47055) Full Text: DOI
Liu, Guixia; Liu, Lili; Li, Caijuan The convergence of Ishikawa-type iterative processes with errors for two contractive mappings in Banach space. (Chinese. English summary) Zbl 1211.47104 J. Hebei Norm. Univ., Nat. Sci. Ed. 30, No. 1, 13-16 (2006). MSC: 47J25 47H10 47H09 47H04 PDFBibTeX XMLCite \textit{G. Liu} et al., J. Hebei Norm. Univ., Nat. Sci. Ed. 30, No. 1, 13--16 (2006; Zbl 1211.47104)
Li, Jun; Huang, Nan Jing; Hwang, Ho Jin; Cho, Yeol Je Stability of iterative procedures with errors for approximating common fixed points of quasi-contractive mappings. (English) Zbl 1081.47066 Appl. Anal. 84, No. 3, 253-267 (2005). Reviewer: S. P. Singh (London, Ontario) MSC: 47J25 47H09 47H10 40A05 PDFBibTeX XMLCite \textit{J. Li} et al., Appl. Anal. 84, No. 3, 253--267 (2005; Zbl 1081.47066) Full Text: DOI
Berinde, Vasile Approximation of fixed points of some nonself generalized \(\varphi\)-contractions. (English) Zbl 1083.54530 Math. Balk., New Ser. 18, No. 1-2, 85-93 (2004). MSC: 54H25 47H10 PDFBibTeX XMLCite \textit{V. Berinde}, Math. Balk., New Ser. 18, No. 1--2, 85--93 (2004; Zbl 1083.54530)
Berinde, Vasile Picard iteration converges faster than Mann iteration for a class of quasi-contractive operators. (English) Zbl 1090.47053 Fixed Point Theory Appl. 2004, No. 2, 97-105 (2004). Reviewer: Poom Kumam (Bangkok) MSC: 47J25 47H10 54H25 PDFBibTeX XMLCite \textit{V. Berinde}, Fixed Point Theory Appl. 2004, No. 2, 97--105 (2004; Zbl 1090.47053) Full Text: DOI EuDML
Huang, Jui-Chi Convergence and stability of iterative procedures with errors for a couple of quasi-contractive mappings in \(q\)-uniformly smooth Banach spaces. (English) Zbl 1065.47058 Far East J. Math. Sci. (FJMS) 10, No. 2, 121-146 (2003). Reviewer: Zhilin Yang (Qingdao) MSC: 47H10 47J25 PDFBibTeX XMLCite \textit{J.-C. Huang}, Far East J. Math. Sci. (FJMS) 10, No. 2, 121--146 (2003; Zbl 1065.47058)
Kang, Shin Min; Liu, Zeqing; Wang, Li Convergence and stability of Ishikawa iterative processes with errors for a pair of quasi-contractive mappings in uniformly convex Banach spaces. (English) Zbl 1066.47067 Far East J. Math. Sci. (FJMS) 9, No. 1, 105-119 (2003). Reviewer: Jürgen Appell (Würzburg) MSC: 47J25 47H10 PDFBibTeX XMLCite \textit{S. M. Kang} et al., Far East J. Math. Sci. (FJMS) 9, No. 1, 105--119 (2003; Zbl 1066.47067)
Tian, Youxian Ishikawa iterative process with errors for a sequence of more generalized quasicontractive mappings. (Chinese. English summary) Zbl 1040.54020 J. Sichuan Norm. Univ., Nat. Sci. 25, No. 5, 472-475 (2002). MSC: 54H25 PDFBibTeX XMLCite \textit{Y. Tian}, J. Sichuan Norm. Univ., Nat. Sci. 25, No. 5, 472--475 (2002; Zbl 1040.54020)
Hao, Jinbiao; Wang, Li; Kang, Shin Min; Shim, Soo Hak Convergence theorems of three-step iteration methods for quasi-contractive mappings. (English) Zbl 1040.47046 EAMJ, East Asian Math. J. 18, No. 2, 261-270 (2002). Reviewer: Muhammad Aslam Noor (Sharjah) MSC: 47J25 47H07 PDFBibTeX XMLCite \textit{J. Hao} et al., EAMJ, East Asian Math. J. 18, No. 2, 261--270 (2002; Zbl 1040.47046)
Agarwal, Ravi P.; Cho, Yeol Je; Li, Jun; Huang, Nan Jing Stability of iterative procedures with errors approximating common fixed points for a couple of quasi-contractive mappings in \(q\)-uniformly smooth Banach spaces. (English) Zbl 1012.65051 J. Math. Anal. Appl. 272, No. 2, 435-447 (2002). Reviewer: W.C.Rheinboldt (Pittsburgh) MSC: 65J15 47J25 47H09 47H10 PDFBibTeX XMLCite \textit{R. P. Agarwal} et al., J. Math. Anal. Appl. 272, No. 2, 435--447 (2002; Zbl 1012.65051) Full Text: DOI
Sastry, K. P. R.; Babu, G. V. R.; Rao, Ch. Srinivasa Convergence of an Ishikawa iteration scheme for a nonlinear quasi-contractive pair of selfmaps of convex metric spaces. (English) Zbl 1039.47050 Indian J. Pure Appl. Math. 33, No. 2, 203-214 (2002). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{K. P. R. Sastry} et al., Indian J. Pure Appl. Math. 33, No. 2, 203--214 (2002; Zbl 1039.47050)
Tian, Youxian Stability of fixed point iteration procedures of the generalized quasi-contractive mapping. (Chinese. English summary) Zbl 1027.47067 J. Sichuan Univ., Nat. Sci. Ed. 38, No. 4, 495-498 (2001). MSC: 47J25 47H10 PDFBibTeX XMLCite \textit{Y. Tian}, J. Sichuan Univ., Nat. Sci. Ed. 38, No. 4, 495--498 (2001; Zbl 1027.47067)
Liu, Zeqing; Zhang, Lili; Cho, Yeol Je Convergence and stability of Ishikawa iterative methods with errors for quasi-contractive mappings in \(q\)-uniformly smooth Banach spaces. (English) Zbl 1035.47052 Appl. Anal. 79, No. 1-2, 277-292 (2001). Reviewer: Peter Zabreiko (Minsk) MSC: 47J25 47H09 65J15 PDFBibTeX XMLCite \textit{Z. Liu} et al., Appl. Anal. 79, No. 1--2, 277--292 (2001; Zbl 1035.47052) Full Text: DOI
Tian, Youxian Quasi-contractive mapping and Ishikawa iteration process with errors. (Chinese. English summary) Zbl 1015.47046 J. Sichuan Univ., Nat. Sci. Ed. 37, No. 6, 839-843 (2000). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{Y. Tian}, J. Sichuan Univ., Nat. Sci. Ed. 37, No. 6, 839--843 (2000; Zbl 1015.47046)
Osilike, M. O. A stable iteration procedure for quasi-contractive maps. (English) Zbl 0847.47042 Indian J. Pure Appl. Math. 27, No. 1, 25-34 (1996). MSC: 47J25 47H09 PDFBibTeX XMLCite \textit{M. O. Osilike}, Indian J. Pure Appl. Math. 27, No. 1, 25--34 (1996; Zbl 0847.47042)
Fan, Zhengyi; Wang, Xuewu The fixed point theorem of the quasi-contractive mapping (48). (Chinese. English summary) Zbl 0840.47042 J. Nat. Sci. Heilongjiang Univ. 11, No. 2, 21-23 (1994). MSC: 47H10 47H09 PDFBibTeX XMLCite \textit{Z. Fan} and \textit{X. Wang}, J. Nat. Sci. Heilongjiang Univ. 11, No. 2, 21--23 (1994; Zbl 0840.47042)
Tian, Youxian A sequence of quasi-contractive mapping and generalized Ishikawa’s iteration. (Chinese. English summary) Zbl 0816.47061 J. Sichuan Univ., Nat. Sci. Ed. 30, No. 3, 331-334 (1993). MSC: 47H09 47H10 47J25 PDFBibTeX XMLCite \textit{Y. Tian}, J. Sichuan Univ., Nat. Sci. Ed. 30, No. 3, 331--334 (1993; Zbl 0816.47061)
Chidume, C. E.; Osilike, M. O. Fixed point iterations for quasi-contractive maps in uniformly smooth Banach spaces. (English) Zbl 0895.47047 Bull. Korean Math. Soc. 30, No. 2, 201-212 (1993). MSC: 47J25 47H10 47H09 46B20 PDFBibTeX XMLCite \textit{C. E. Chidume} and \textit{M. O. Osilike}, Bull. Korean Math. Soc. 30, No. 2, 201--212 (1993; Zbl 0895.47047)
Chidume, C. E. Approximation of fixed points of quasi-contractive mappings in \(L_ p\) spaces. (English) Zbl 0761.47043 Indian J. Pure Appl. Math. 22, No. 4, 273-286 (1991). Reviewer: S.K.Chatterjea (Calcutta) MSC: 47J25 47H10 54H25 PDFBibTeX XMLCite \textit{C. E. Chidume}, Indian J. Pure Appl. Math. 22, No. 4, 273--286 (1991; Zbl 0761.47043)
Liu, Qihou On Naimpally and Singh’s open questions. (English) Zbl 0625.47044 J. Math. Anal. Appl. 124, 157-164 (1987). MSC: 47H10 47H09 47J25 PDFBibTeX XMLCite \textit{Q. Liu}, J. Math. Anal. Appl. 124, 157--164 (1987; Zbl 0625.47044) Full Text: DOI
Chidume, C. E. On the Ishikawa fixed points iterations for quasi-contractive mappings. (English) Zbl 0622.47061 J. Niger. Math. Soc. 4(1987), 1-11 (1985). MSC: 47J25 47H10 47H09 PDFBibTeX XMLCite \textit{C. E. Chidume}, J. Niger. Math. Soc. 4, 1--11 (1987; Zbl 0622.47061)
You, Zhaoyong; Xu, Zongben Ergodic convergence for fixed points and variational inequality of a class of nonlinear mappings. (Chinese. English summary) Zbl 0603.47046 J. Xi’an Jiaotong Univ. 19, No. 2, 1-10 (1985). MSC: 47H10 47H07 PDFBibTeX XMLCite \textit{Z. You} and \textit{Z. Xu}, J. Xi'an Jiaotong Univ. 19, No. 2, 1--10 (1985; Zbl 0603.47046)