References

TOPOLOGICAL DIVISOR OF ZERO PERTURBATION FUNCTIONS


[1] K. Astala and H. O. Tylli, On the bounded compact approximation property and measures of non-compactness, J. Funct. Anal. 70 (1987), 388-401.

[2] B. Aupetit, Propriétés Spectrales des Algèbres de Banach, Lecture Notes in Mathematics 735 (1979).

[3] F. F. Bonsall and J. Duncan, Numerical ranges of operators on normed spaces and of elements of normed algebras, London Math. Soc. Lecture Note Series, 1971.

[4] F. F. Bonsall and J. Duncan, Complete Normed Algebras, Springer-Verlag, 1973.

[5] R. Bouldin, The essential minimum modulus, Indiana Univ. Math. J. 30 (1981), 513-517.

[6] S. R. Caradus, W. E. Plaffenberger and B. Yood, Calkin Algebras and Algebras of Operators on Banach Spaces, M. Dekker, New York, 1974.

[7] J. B. Conway, A Course in Functional Analysis, Second Edition, Springer-Verlag, New York, 1990.

[8] R. G. Douglas, Banach Algebra Techniques in Operator Theory, Academic Press, 1972.

[9] D. E. Edmunds and W. D. Evans, Spectral Theory and Differential Operators, Clarendon Press, Oxford, 1987.

[10] F. Galaz-Fontes, Measures of non-compactness and upper semi-Fredholm perturbation theorems, Proc. Amer. Math. Soc. 118 (1993), 891-897.

[11] F. Galaz-Fontes, Approximation by semi-Fredholm operators, Proc. Amer. Math. Soc. 120 (1994), 1219-1222.

[12] H. A. Gindler and A. E. Taylor, The minimum modulus of a linear operator and its use in spectral theory, Studia Math. 22 (1962/63), 15-41.

[13] S. Goldberg, Unbounded Linear Operators, McGraw-Hill, New York, 1966.

[14] M. Gonzalez and A. Martinon, Operational quantities characterizing semi-Fredholm operators, Studia Math. 114 (1995), 13-27.

[15] P. Gopalraj and A. Ströh, On the essential lower bound of elements in von Neumann algebras, Integral Equations Operator Theory 49 (2004), 379-386.

[16] R. Kadison and J. Ringrose, Fundamentals of the Theory of Operator Algebras, Academic Press, Orlando, Vol. I, 1983.

[17] T. Kato, Perturbation theory for nullity, deficiency and other quantities of linear operators, J. Analyse Math. 6 (1958), 261-322.

[18] A. Lebow and M. Schechter, Semigroups of operators and measures of non-compactness, J. Funct. Anal. 7 (1971), 1-26.

[19] M. Mekhta, Fonctions perturbation et formules du rayon spectral essentiel et de distance au spectrale essentiel, J. Operator Theory 51 (2004), 3-18.

[20] G. J. Murphy and T. T. West, Spectral radius formulae, Proc. Edinburgh Math. Soc. (2) 22(3) (1979), 271-275.

[21] A. Pietsch, Operators Ideals, VEB Deutsch Verlag der Wissenschaften, Berlin, 1978.

[22] C. E. Rickart, General Theory of Banach Algebras, Van Nostrand, Princeton, 1960.

[23] M. Schechter, Quantities related to strictly singular operators, Indiana Univ. Math. J. 21 (1972), 473-478.

[24] J. G. Stampfli and J. P. Williams, Growth conditions and the numerical range in a Banach algebra, Tôhoku Math. J. 20 (1968), 417-424.

[25] H. O. Tylli, On the asymptotic behaviour of some quantities related to semi-Fredholm operators, J. London Math. Soc. 31(2) (1985), 340-348.

[26] H. O. Tylli, The essential norm of an operator is not self-dual, Israel J. Math. 91 (1995), 93-110.

[27] J. Zemánek, Geometric interpretations of the essential minimum modulus, Invariant subspaces and other topics, Operator Theory: Adv. Appl. Birkhäuser, Basel-Boston, Mass. 6 (1982), 225-227.

[28] J. Zemánek, The surjectivity radius, packing numbers and boundedness below of linear operators, Int. Equa. Oper. Theory 6 (1983), 372-384.

[29] J. Zemánek, The semi-Fredholm radius of a linear operator, Bull. Polish Acad. Sci. Math. 32 (1984), 67-76.

[30] J. Zemánek, Geometric characteristics of semi-Fredholm operators and their asymptotic behaviour, Studia Math. 80 (1984), 219-234.

[31] S. Živković, Semi-Fredholm operators and perturbation functions, Filomat 11 (1997), 77-88.

[32] S. Živković, Semi-Fredholm operators and perturbations, Publ. Inst. Math. (Beograd) (N.S.) 61(75) (1997), 73-89.

[33] S. Živković, Measures of non-strict-singularity and non-strict-cosingularity, Mat. Vesnik 54 (2002), 1-7.