Anton Zettl

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All published works

Action	Title	Year	Authors
+ PDF Chat	Friedrichs extension of singular symmetric differential operators	2023	Qinglan Bao Guangsheng Wei Anton Zettl
+	Characterization of symmetric operators and their Friedrichs extension for singular Sturm-Liouville problems	2022	Qinglan Bao Guangsheng Wei Anton Zettl
+ PDF Chat	The Friedrichs extension of regular symmetric differential operators	2022	Qing an Bao Guangsheng Wei Anton Zettl
+	5 Inverse Sturm–Liouville problems with finite spectrum	2021	Anton Zettl
+	7 Spectral parameter in the boundary conditions	2021	Anton Zettl
+	Recent Developments in Sturm-Liouville Theory	2021	Anton Zettl
+	A class of dissipative differential operators of order three	2021	Tao Wang Ji-jun Ao Anton Zettl
+	Left-Definite Variations of the Classical Fourier Expansion Theorem, Part II	2021	Lance L. Littlejohn Edward L. Smith Anton Zettl
+ PDF Chat	Ordinary Differential Operators	2019	Aiping Wang Anton Zettl
+	Self-adjoint and symmetric boundary conditions	2019	Aiping Wang Anton Zettl
+	Quasi-differential expressions and equations	2019	Aiping Wang Anton Zettl
+	Self-adjoint operators	2019	Aiping Wang Anton Zettl
+	The Lagrange identity and maximal and minimal operators	2019	Aiping Wang Anton Zettl
+	An alternate proof of Kato’s inequality	2019	Man Kam Kwong Anton Zettl
+	Characterization of self-adjoint domains for regular even order <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>C</mml:mi> </mml:mrow> </mml:math>-symmetric differential operators	2019	Jiong Sun Qinglan Bao Xiaoling Hao Anton Zettl
+	NEW CANONICAL FORMS OF SELF-ADJOINT BOUNDARY CONDITIONS FOR REGULAR DIFFERENTIAL OPERATORS OF ORDER FOUR	2019	Qinglan Bao Jiong Sun Xiaoling Hao Anton Zettl
+	Proof of the deficiency index conjecture	2018	Aiping Wang Anton Zettl
+	A symmetric GKN-type theorem and symmetric differential operators	2018	Aiping Wang Anton Zettl
+	Characterization of domains of symmetric and self-adjoint ordinary differential operators	2018	Aiping Wang Anton Zettl
+	Inequalities among eigenvalues of Sturm Liouville equations with periodic coefficients	2017	Yaping Yuan Jiong Sun Anton Zettl
+	Dependence of eigenvalues of fourth-order differential equations with discontinuous boundary conditions on the problem	2017	Xiao-xia Lv Ji-jun Ao Anton Zettl
+	Eigenvalues of Sturm-Liouville problems with discontinuous boundary conditions	2017	Aiping Wang Anton Zettl
+	A GKN Theorem for symmetric operators	2017	Aiping Wang Anton Zettl
+	Characterization of domains of self-adjoint ordinary differential operators of any order, even or odd	2017	Xiaoling Hao Maozhu Zhang Jiong Sun Anton Zettl
+	Eigenvalues of periodic Sturm Liouville problems	2016	Yaping Yuan Jiong Sun Anton Zettl
+	Dissipative operators, symplectic geometry, and limit-circle solutions	2016	Siqin Yao Jiong Sun Anton Zettl
+	Self-adjoint Sturm-Liouville problems with an infinite number of boundary conditions	2016	Zhao Yingchun Jiong Sun Anton Zettl
+	Survey Article: Self-adjoint ordinary differential operators and their spectrum	2015	Anton Zettl Jiong Sun
+ PDF Chat	The Sturm-Liouville Friedrichs extension	2015	Siqin Yao Jiong Sun Anton Zettl
+ PDF Chat	Self-adjoint Sturm-Liouville problems with discontinuous boundary conditions	2015	Aiping Wang Anton Zettl
+	Finite spectrum of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" display="inline" overflow="scroll"><mml:mn>2</mml:mn><mml:mi>n</mml:mi></mml:math>th order boundary value problems	2014	Ji-jun Ao Jiong Sun Anton Zettl
+	Eigenvalues of limit-point Sturm–Liouville problems	2014	Maozhu Zhang Jiong Sun Anton Zettl
+	Symplectic geometry and dissipative differential operators	2014	Siqin Yao Jiong Sun Anton Zettl
+	Green's function for two-interval Sturm-Liouville problems	2013	Aiping Wang Anton Zettl
+ PDF Chat	HALF INVERSE PROBLEMS FOR QUADRATIC PENCILS OF STURM-LIOUVILLE OPERATORS	2012	Chuan‐Fu Yang Anton Zettl
+	Self-adjoint domains, symplectic geometry, and limit-circle solutions	2012	Siqin Yao Jiong Sun Anton Zettl
+	The Spectrum of Singular Sturm-Liouville Problems With Eigenparameter Dependent Boundary Conditions and Its Approximation	2012	Maozhu Zhang Jiong Sun Anton Zettl
+	Sturm-Liouville eigenvalue characterizations	2012	Paul B. Bailey Anton Zettl
+	Fourth order canonical forms of singular self-adjoint boundary conditions	2012	Xiaoling Hao Jiong Sun Anton Zettl
+	Construction of regular and singular Green's functions	2012	Aiping Wang Jerry Ridenhour Anton Zettl
+	HALF INVERSE PROBLEMS FOR QUADRATIC PENCILS OF STURM-LIOUVILLE OPERATORS	2012	Chuan‐Fu Yang Anton Zettl
+	Equivalence of Fourth Order Boundary Value Problems and Matrix Eigenvalue Problems	2011	Ji-jun Ao Jiong Sun Anton Zettl
+	The spectrum of differential operators and square-integrable solutions	2011	Xiaoling Hao Jiong Sun Anton Zettl
+	Matrix representations of fourth order boundary value problems with finite spectrum	2011	Ji-jun Ao Jiong Sun Anton Zettl
+	Canonical forms of self-adjoint boundary conditions for differential operators of order four	2011	Xiaoling Hao Jiong Sun Anton Zettl
+	Inverse Sturm–Liouville problems with finite spectrum	2011	Qingkai Kong Anton Zettl
+	New proofs and extensions of Sylvester’s and Johnson’s inertia theorems to non-Hermitian matrices	2011	Man Kam Kwong Anton Zettl
+	Characterization of Domains of Self-Adjoint Ordinary Differential Operators II	2011	Xiaoling Hao Jiong Sun Aiping Wang Anton Zettl
+	The classification of self-adjoint boundary conditions of differential operators with two singular endpoints	2011	Aiping Wang Jiong Sun Anton Zettl
+	Real-parameter square-integrable solutions and the spectrum of differential operators	2010	Xiaoling Hao Jiong Sun Anton Zettl
+	Regular self-adjoint problems	2010	Anton Zettl
+	Two-point singular boundary value problems	2010	Anton Zettl
+	Singular left-definite problems	2010	Anton Zettl
+	Singular indefinite problems	2010	Anton Zettl
+	Singular initial value problems	2010	Anton Zettl
+	Regular left-definite and indefinite problems	2010	Anton Zettl
+	Scalar initial value problems	2010	Anton Zettl
+	Two-point regular boundary value problems	2010	Anton Zettl
+	Singular self-adjoint problems	2010	Anton Zettl
+	The study of Jacobi and cyclic Jacobi matrix eigenvalue problems using Sturm–Liouville theory	2010	Qingkai Kong Anton Zettl
+	Matrix Representations of Sturm–Liouville Problems with Finite Spectrum	2009	Qingkai Kong Hans Volkmer Anton Zettl
+	Characterization of domains of self-adjoint ordinary differential operators	2008	Aiping Wang Jiong Sun Anton Zettl
+	Continuous spectrum and square-integrable solutions of differential operators with intermediate deficiency index	2008	Jiong Sun Aiping Wang Anton Zettl
+	The classification of self-adjoint boundary conditions: Separated, coupled, and mixed	2008	Aiping Wang Jiong Sun Anton Zettl
+	Limits of Sturm–Liouville eigenvalues when the interval shrinks to an end point	2008	Qingkai Kong Hongyou Wu Anton Zettl
+	Geometric aspects of Sturm–Liouville problems III. Level surfaces of the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si8.gif" overflow="scroll"><mml:mi>n</mml:mi></mml:math>th eigenvalue	2007	Xifang Cao Qingkai Kong Hongyou Wu Anton Zettl
+	Two-Interval Sturm–Liouville Operators in Direct Sum Spaces with Inner Product Multiples	2007	Jiong Sun Aiping Wang Anton Zettl
+	Left-definite variations of the classical Fourier expansion theorem.	2007	Lance L. Littlejohn Anton Zettl
+ PDF Chat	Inverse spectral theory for Sturm-Liouville problems with finite spectrum	2006	Hans Volkmer Anton Zettl
+	Two-interval Sturm–Liouville operators in modified Hilbert spaces	2006	Aiping Wang Jiong Sun Anton Zettl
+	Sturm–Liouville problems with singular non‐selfadjoint boundary conditions	2005	Walter Eberhard Gerhard Freiling Anton Zettl
+ PDF Chat	Erratum to Spectral exactness and spectral inclusion for singular left definite Sturm-Liouvelle problems	2005	Marco Marietta Anton Zettl
+	Floquet theory for left-definite Sturm–Liouville problems	2005	Marco Marletta Anton Zettl
+	Sturm-Liouville theory	2005	Anton Zettl
+	Singular left-definite Sturm–Liouville problems	2004	Qingkai Kong Haotian Wu Anton Zettl
+	Multiplicity of Sturm–Liouville eigenvalues	2004	Qingkai Kong Haotian Wu Anton Zettl
+	Regular Approximations of Singular Sturm-Liouville Problems with Limit-Circle Endpoints	2004	Lingju Kong Qingkai Kong Haotian Wu Anton Zettl
+	Spectral exactness and spectral inclusion for singular left-definite Sturm-Liouville problems	2004	Marco Marietta Anton Zettl
+	Geometric aspects of Sturm-Liouville problems II. Space of boundary conditions for left-definiteness	2003	Kevin Haertzen Qingkai Kong Hongyou Wu Anton Zettl
+ PDF Chat	Sturm-Liouville Problems Whose Leading Coefficient Function Changes Sign	2003	Xifang Cao Qingkai Kong Hongyou Wu Anton Zettl
+	Indefinite Sturm–Liouville problems	2003	Qingkai Kong Haotian Wu Anton Zettl Manfred Möller
+	On some eigenvalue problems in fuel–cell dynamics	2003	Paul B. Bailey J. Billingham Richard Cooper W. N. Everitt A. C. King Qingkai Kong Haotian Wu Anton Zettl
+	The Kallman-Rota inequality; a survey	2003	W. N. Everitt Anton Zettl
+	Counting and computing eigenvalues of left-definite Sturm–Liouville problems	2002	Marco Marletta Anton Zettl
+	Some Spectral Properties of the Heun Differential Equation	2002	Paul B. Bailey W. N. Everitt Don Hinton Anton Zettl
+	Sturm–Liouville Problems with Finite Spectrum	2001	Qingkai Kong Haotian Wu Anton Zettl
+	Left-Definite Sturm–Liouville Problems	2001	Qingkai Kong Haotian Wu Anton Zettl
+	Algorithm 810: The SLEIGN2 Sturm-Liouville Code	2001	Paul B. Bailey W. N. Everitt Anton Zettl
+ PDF Chat	Inequalities and eigenvalues of Sturm-Liouville problems near a singular boundary	2001	W. N. Everitt Marco Marletta Anton Zettl
+	On a computer assisted proof of the existence of eigenvalues below the essential spectrum of the Sturm–Liouville problem	2000	B. M. Brown D. K. R. McCormack Anton Zettl
+	Geometric aspects of Sturm—Liouville problems I. Structures on spaces of boundary conditions	2000	Qingkai Kong Haotian Wu Anton Zettl
+	The Friedrichs Extension of Singular Differential Operators	2000	Marco Marletta Anton Zettl
+	Dependence of the nth Sturm–Liouville Eigenvalue on the Problem	1999	Qingkai Kong Hongyou Wu Anton Zettl
+	On the existence of an eigenvalue below the essential spectrum	1999	B. M. Brown D. K. R. McCormack Anton Zettl
+	Inequalities among eigenvalues of Sturm–Liouville problems	1999	M. S. P. Eastham Qingkai Kong Haotian Wu Anton Zettl
+	Sturm—Liouville problems and discontinuous eigenvalues	1999	W. N. Everitt Manfred Möller Anton Zettl
+	Dependence of the nth SturmLiouville Eigenvalue on the Problem	1999	Qingkai Kong Hongyou Wu Anton Zettl
+	Discontinuous dependence of the n-th Sturm-Liouville eigenvalue	1997	W. N. Everitt Manfred Möller Anton Zettl
+	Dependence of Eigenvalues on the Problem	1997	Qingkai Kong Haotian Wu Anton Zettl
+	Eigenvalues of Regular Sturm–Liouville Problems	1996	Qingkai Kong Anton Zettl
+	Dependence of Eigenvalues of Sturm–Liouville Problems on the Boundary	1996	Qingkai Kong Anton Zettl
+	Regular and singular Sturm–Liouville problems with coupled boundary conditions	1996	Paul B. Bailey W. N. Everitt Anton Zettl
+	Interval Oscillation Conditions for Difference Equations	1995	Qingkai Kong Anton Zettl
+	Eigenvalue Computations for Regular Matrix Sturm-Liouville Problems	1995	H. I. Dwyer Anton Zettl
+	Semi-boundedness of Ordinary Differential Operators	1995	Manfred Möller Anton Zettl
+	Symmetrical Differential Operators and Their Friedrichs Extension	1995	Manfred Möller Anton Zettl
+	Computing eigenvalues of regular Sturm-Liouville problems	1994	H. I. Dwyer Anton Zettl
+	Linear Ordinary Differential Equations	1994	Qingkai Kong Anton Zettl
+ PDF Chat	Book Review: Global properties of linear ordinary differential equations	1993	Anton Zettl
+	Weighted norm inequalities for the quasi-derivatives of ordinary differential operators	1993	Manfred Möller Anton Zettl
+	Regular approximations of singular Sturm-Liouville problems	1993	Paul B. Bailey W. N. Everitt Joachim Weidmann Anton Zettl
+ PDF Chat	Nullspaces, representations and factorizations of quasi-differential expressions	1993	David Race Anton Zettl
+	On the commutativity of certain quasi-differential expressions II	1993	Hilbert Frentzen David Race Anton Zettl
+	Differential Operators Generated by a Countable Number of Quasi-Differential Expressions on the Real Line	1992	W. N. Everitt Anton Zettl
+	Singular Sturm-Liouville Problems: The Friedrichs Extension and Comparison of Eigenvalues	1992	Heinz‐Dieter Niessen Anton Zettl
+ PDF Chat	Norm Inequalities for Derivatives and Differences	1992	Man Kam Kwong Anton Zettl
+	Characterisation of the factors of quasi-differential expressions	1992	David Race Anton Zettl
+	The difference operator	1992	Man Kam Kwong Anton Zettl
+	Unit weight functions	1992	Man Kam Kwong Anton Zettl
+ PDF Chat	Eigenvalue and eigenfunction computations for Sturm-Liouville problems	1991	Paul B. Bailey Anton Zettl
+	Computing Eigenvalues of Singular Sturm-Liouville Problems	1991	Paul B. Bailey W. N. Everitt Anton Zettl
+	Norm Inequalities for the Powers of a Matrix	1991	Man Kam Kwong Anton Zettl
+	On the Commutativity of Certain Quasidifferential Expressions I	1990	David Race Anton Zettl
+	The Friedrichs extension of regular ordinary differential operators	1990	Heinz‐Dieter Niessen Anton Zettl
+	Proceedings of the Focused Research Program on Spectral Theory and Boundary Value Problems, Vol. 4: Nonlinear Differential Equations	1989	Hans G. Kaper Man Kam Kwong Anton Zettl
+	Proceedings of the Focused Research Program on Spectral Theory and Boundary Value Problems, Vol. 3: Linear Differential Equations and Systems	1989	Hans G. Kaper Man Kam Kwong Anton Zettl
+	Singular Self-Adjoint Sturm–Liouville Problems: II. Interior Singular Points	1988	Allan M. Krall Anton Zettl
+ PDF Chat	Regularization of a Sturm-Liouville problem with an interior singularity using quasiderivatives	1988	F. V. Atkinson W. N. Everitt Anton Zettl
+ PDF Chat	Singular selfadjoint Sturm-Liouville problems	1988	Allan M. Krall Anton Zettl
+ PDF Chat	Landau’s inequality for the difference operator	1988	Man Kam Kwong Anton Zettl
+	Some comments on Sturm-Liouville eigenvalue problems with interior singularities	1987	W. N. Everitt J. Gunson Anton Zettl
+	Extremals in Landau's inequality for the difference operator	1987	Man Kam Kwong Anton Zettl
+	Landau’s Inequality for the Differential and Difference Operators	1987	Man Kam Kwong Anton Zettl
+	Problems on Landau’s Inequality	1987	Man Kam Kwong Anton Zettl
+ PDF Chat	Sturm-liouville differential operators in direct sum spaces	1986	W. N. Everitt Anton Zettl
+	Characterizations of the Friedrichs Extensions of Singular Sturm–Liouville Expressions	1986	Hans G. Kaper Man Kam Kwong Anton Zettl
+	Best constants in norm inequalities for derivatives on a half-line	1985	Zachary Franco Hans G. Kaper Man Kam Kwong Anton Zettl
+	Spectral theory of Sturm-Liouville differential operators: proceedings of the 1984 workshop	1984	Hans G. Kaper Anton Zettl
+	Spectral Theory of Sturm-Liouville Differential Operators: Proceedings of the 1984 Workshop. Held at Argonne National Laboratory May 15 - June 15, 1984	1984	Hans G. Kaper Anton Zettl G. W. Pieper
+	Regularizing Transformations for Certain Singular Sturm–Liouville Boundary Value Problems	1984	Hans G. Kaper Man Kam Kwong Anton Zettl
+	Singular Sturm?Liouville problems with nonnegative and indefinite weights	1984	Hans G. Kaper Man Kam Kwong Anton Zettl
+	Differential operators and quadratic inequalities with a degenerate weight	1984	W. N. Everitt Man Kam Kwong Anton Zettl
+	Full- and partial-range eigenfunction expansions for Sturm-Liouville problems with indefinite weights	1984	Hans G. Kaper Man Kam Kwong C.G. Lekkerkerker Anton Zettl
+	Landau's inequality	1984	Man Kam Kwong Anton Zettl
+	Weighted Landau inequalities	1983	Jerome A. Goldstein Man Kam Kwong Anton Zettl
+	Asymptotically constant functions and second order linear oscillation	1983	Man Kam Kwong Anton Zettl
+	Lower bounds for the spectrum of ordinary differential operators	1983	W. D. Evans Man Kam Kwong Anton Zettl
+	Oscillation of Eigenfunctions of Weighted Regular Sturm-Liouville Problems	1983	W. N. Everitt Man Kam Kwong Anton Zettl
+	Bounds for the best constant in Landau/s inequality on the line	1983	Zachary Franco Hans G. Kaper Man Kam Kwong Anton Zettl
+	Non-self-adjoint operators and their essential spectra	1983	W. D. Evans Roger T. Lewis Anton Zettl
+	A new approach to second order linear oscillation theory	1983	Man Kam Kwong Anton Zettl
+	Integral inequalities and second order linear oscillation	1982	Man Kam Kwong Anton Zettl
+	Linear transport theory and an indefinite Sturm-Liouville problem	1982	Hans G. Kaper C.G. Lekkerkerker Anton Zettl
+	Discreteness conditions for the spectrum of ordinary differential operators	1981	Man Kam Kwong Anton Zettl
+	Commuting linear differential expressions	1981	M. Giertz Man Kam Kwong Anton Zettl
+	Weighted norm inequalities of sum form involving derivatives	1981	Man Kam Kwong Anton Zettl
+	Norm inequalities of product form in weighted <i>L<sup>p</sup></i> spaces	1981	Man Kam Kwong Anton Zettl
+	Ramifications of Landau's inequality	1980	Man Kam Kwong Anton Zettl
+	Remarks on best constants for norm inequalities among powers of an operator	1979	Man Kam Kwong Anton Zettl
+ PDF Chat	An extension of the Hardy-Littlewood inequality	1979	Man Kam Kwong Anton Zettl
+	On a Class of Integral Inequalities	1978	W. N. Everitt Anton Zettl
+	Levinson's limit-point criterion and powers	1978	W. D. Evans Anton Zettl
+	PRODUCTS OF DIFFERENTIAL EXPRESSIONS WITHOUT SMOOTHNESS ASSUMPTIONS	1978	W. N. Everitt Anton Zettl
+	Norm inequalities involving derivatives	1978	W. D. Evans Anton Zettl
+	Dirichlet and separation results for Schrödinger-type operators	1978	W. D. Evans Anton Zettl
+ PDF Chat	The Deficiency Index Problem for Powers of Ordinary Differential Expressions	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	Interval Limit-Point Criteria for Differential Expressions and their Powers	1977	W. D. Evans Anton Zettl
+	The number of integrable-square solutions of products of differential expressions	1977	W. N. Everitt Anton Zettl
+	Higher order limit-point criteria	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	Applications of perturbation theory	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	Functional analytic preliminaries	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	Second order limit-point, limit-circle conditions	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	Linear differential operators and the general classification theory of deficiency indices	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	The deficiency index problem for polynomials in symmetric differential expressions	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	Second-order differential expressions whose squares are limit-3	1977	M. S. P. Eastham Anton Zettl
+	Conditions on the coefficients for all powers to be limit-point	1977	Robert M. Kauffman Thomas T. Read Anton Zettl
+	On the Deficiency Indices of Powers of Real 2<i>nth</i> -Order Symmetric Differential Expressions	1976	W. D. Evans Anton Zettl
+	Perturbation Theory of Deficiency Indices of Differential Operators	1976	Anton Zettl
+	Separation for Differential Operators and the L p Spaces	1976	Anton Zettl
+	Limit point conditions for powers	1976	Anton Zettl
+	POWERS OF REAL SYMMETRIC DIFFERENTIAL EXPRESSIONS WITHOUT SMOOTHNESS ASSUMPTIONS	1976	Anton Zettl
+ PDF Chat	Separation for differential operators and the 𝐿^{𝑝} spaces	1976	Anton Zettl
+	1.—An Algorithm for the Construction of Limit Circle Expressions	1976	Anton Zettl
+	4.—An Algorithm for the Construction of all Disconjugate Operators.	1976	Anton Zettl
+ PDF Chat	Formally self-adjoint quasi-differential operators	1975	Anton Zettl
+	PERTURBATION OF THE LIMIT CIRCLE CASE	1975	Anton Zettl
+	17.—The Limit-point and Limit-circle Cases for Polynomials in a Differential Operator	1975	Anton Zettl
+	20.—Deficiency Indices of Polynomials in Symmetric Differential Expressions, II	1975	Anton Zettl
+ PDF Chat	General Theory of the Factorization of Ordinary Linear Differential Operators	1974	Anton Zettl
+	Deficiency indices of polynomials in symmetric differential expressions	1974	Anton Zettl
+ PDF Chat	General theory of the factorization of ordinary linear differential operators	1974	Anton Zettl
+	On the limit point classification of second order differential equations	1973	James S. W. Wong Anton Zettl
+	Explicit Conditions for the Factorization of nth Order Linear Differential Operators	1973	Anton Zettl
+ PDF Chat	Explicit conditions for the factorization of $n$th order linear differential operators	1973	Anton Zettl
+ PDF Chat	Factorization and disconjugacy of third order differential equations	1972	Anton Zettl
+ PDF Chat	Factorization and Disconjugacy of Third Order Differential Equations	1972	Anton Zettl
+ PDF Chat	Factorization of differential operators	1971	Anton Zettl
+	Shorter Notes: Factorization of Differential Operators	1971	Anton Zettl
+ PDF Chat	Square integrable solutions of 𝐿𝑦=𝑓(𝑡,𝑦)	1970	Anton Zettl
+	Adjointness in Nonadjoint Boundary Value Problems	1969	Anton Zettl
+	A note on square integrable solutions of linear differential equations	1969	Anton Zettl
+	A Note on Square Integrable Solutions of Linear Differential Equations	1969	Anton Zettl
+	Adjoint and Self-Adjoint Boundary Value Problems with Interface Conditions	1968	Anton Zettl
+	Some Identities Related to Polya's Property W for Linear Differential Equations	1967	Anton Zettl
+ PDF Chat	Some identities related to Pólya’s property 𝑊 for linear differential equations	1967	Anton Zettl
+ PDF Chat	Hermitian and anti-hermitian properties of Green’s matrices	1966	Earl A. Coddington Anton Zettl
+ PDF Chat	The Lack of Self-Adjointness in Three Point Boundary Value Problems	1966	Anton Zettl
+ PDF Chat	The lack of self-adjointness in three point boundary value problems	1966	Anton Zettl
+ PDF Chat	Adjoint Linear Differential Operators	1965	Anton Zettl

Common Coauthors

Coauthor	Papers Together
Man Kam Kwong	33
Jiong Sun	27
Qingkai Kong	23
W. N. Everitt	19
Hans G. Kaper	11
Aiping Wang	11
Haotian Wu	10
Thomas T. Read	8
Xiaoling Hao	8
Robert M. Kauffman	8
Aiping Wang	8
Paul B. Bailey	8
Hongyou Wu	6
Manfred Möller	6
W. D. Evans	5
Ji-jun Ao	5
David Race	4
Marco Marletta	4
Siqin Yao	4
Qinglan Bao	4
Maozhu Zhang	3
Guangsheng Wei	3
Xifang Cao	2
Lance L. Littlejohn	2
Chuan‐Fu Yang	2
Heinz‐Dieter Niessen	2
Marco Marietta	2
Hans Volkmer	2
C.G. Lekkerkerker	2
D. K. R. McCormack	2
Allan M. Krall	2
H. I. Dwyer	2
Zachary Franco	2
Yaping Yuan	2
M. S. P. Eastham	2
B. M. Brown	2
Richard Cooper	1
Qing an Bao	1
Tao Wang	1
J. Gunson	1
James S. W. Wong	1
Hilbert Frentzen	1
Zhao Yingchun	1
Xiao-xia Lv	1
Kevin Haertzen	1
W. D. Evans	1
Aiping Wang	1
M. Giertz	1
Earl A. Coddington	1
J. Billingham	1

Commonly Cited References

Action	Title	Year	Authors	# of times referenced
+	Linear differential operators	1967	M. A. Naĭmark	49
+ PDF Chat	Spectral Theory of Ordinary Differential Operators	1987	Joachim Weidmann	37
+	Sturm-Liouville theory	2005	Anton Zettl	26
+ PDF Chat	Formally self-adjoint quasi-differential operators	1975	Anton Zettl	25
+	Characterization of domains of self-adjoint ordinary differential operators	2008	Aiping Wang Jiong Sun Anton Zettl	19
+	Semi-boundedness of Ordinary Differential Operators	1995	Manfred Möller Anton Zettl	19
+	Linear Operators in Hilbert Spaces	1980	Joachim Weidmann	18
+	<i>Theory of Ordinary Differential Equations</i>	1956	Earl A. Coddington Norman Levinson T. Teichmann	17
+	Dependence of the nth Sturm–Liouville Eigenvalue on the Problem	1999	Qingkai Kong Hongyou Wu Anton Zettl	17
+	Singular Sturm-Liouville Problems: The Friedrichs Extension and Comparison of Eigenvalues	1992	Heinz‐Dieter Niessen Anton Zettl	16
+ PDF Chat	Boundary Value Problems and Symplectic Algebra for Ordinary Differential and Quasi-differential Operators	1998	W. N. Everitt Lawrence Markus	15
+	Regular approximations of singular Sturm-Liouville problems	1993	Paul B. Bailey W. N. Everitt Joachim Weidmann Anton Zettl	14
+	Symmetrical Differential Operators and Their Friedrichs Extension	1995	Manfred Möller Anton Zettl	14
+	Eigenvalues of Regular Sturm–Liouville Problems	1996	Qingkai Kong Anton Zettl	13
+	Equivalence, adjoints and symmetry of quasi-differential expressions with matrix-valued coefficients and polynomials in them	1982	Hilbert Frentzen	13
+	Sturm‐Liouville Theory	2006	James J. Kelly	12
+	Characterization of Domains of Self-Adjoint Ordinary Differential Operators II	2011	Xiaoling Hao Jiong Sun Aiping Wang Anton Zettl	12
+ PDF Chat	Partial Differential Equations	1988	Shiing-Shen Chern	12
+	The classification of self-adjoint boundary conditions: Separated, coupled, and mixed	2008	Aiping Wang Jiong Sun Anton Zettl	12
+	Dependence of Eigenvalues on the Problem	1997	Qingkai Kong Haotian Wu Anton Zettl	12
+	Inequalities among eigenvalues of Sturm–Liouville problems	1999	M. S. P. Eastham Qingkai Kong Haotian Wu Anton Zettl	12
+	Discontinuous dependence of the n-th Sturm-Liouville eigenvalue	1997	W. N. Everitt Manfred Möller Anton Zettl	11
+	Automatic Solution of the Sturm-Liouville Problem	1978	Paul B. Bailey Marilyn K. Gordon L. F. Shampine	11
+	On the unboundedness below of the Sturm—Liouville operator	1999	Manfred Möller	11
+ PDF Chat	Perturbation Theory for Linear Operators	1995	Tosio Kato	11
+	Spectral Theory & Computational Methods of Sturm-Liouville Problems	2021	Don Hinton	10
+	On the theory of singular differential operators	1953	I. M. Glazman	10
+ PDF Chat	Sturm-liouville differential operators in direct sum spaces	1986	W. N. Everitt Anton Zettl	10
+	The Friedrichs extension of regular ordinary differential operators	1990	Heinz‐Dieter Niessen Anton Zettl	10
+ PDF Chat	On the mean-value theorem corresponding to a given linear homogeneous differential equation	1922	Georg Pólya	9
+ PDF Chat	The Deficiency Index Problem for Powers of Ordinary Differential Expressions	1977	Robert M. Kauffman Thomas T. Read Anton Zettl	9
+	Geometric aspects of Sturm—Liouville problems I. Structures on spaces of boundary conditions	2000	Qingkai Kong Haotian Wu Anton Zettl	9
+	�ber gew�hnliche Differentialgleichungen mit Singularit�ten und die zugeh�rigen Entwicklungen willk�rlicher Funktionen	1910	Hermann Weyl	9
+	On the self-adjoint extensions of symmetric ordinary differential operators with middle deficiency indices	1986	Jiong Sun	9
+	Sturm–Liouville Problems with Finite Spectrum	2001	Qingkai Kong Haotian Wu Anton Zettl	9
+	Oscillation theory of ordinary linear differential equations	1969	John H. Barrett	9
+ PDF Chat	Complex symplectic geometry with applications to ordinary differential operators	1999	W. N. Everitt Lawrence Markus	9
+	On the Square of a Formally Self-Adjoint Differential Expression	1969	Jyoti Chaudhuri W. N. Everitt	9
+	ON NECESSARY AND SUFFICIENT CONDITIONS FOR THE EXISTENCE OF CARATHÉODORY SOLUTIONS OF ORDINARY DIFFERENTIAL EQUATIONS	1978	W. N. Everitt David Race	9
+	Real-parameter square-integrable solutions and the spectrum of differential operators	2010	Xiaoling Hao Jiong Sun Anton Zettl	9
+	Adjoint and Self-Adjoint Boundary Value Problems with Interface Conditions	1968	Anton Zettl	8
+	INTEGRABLE-SQUARE SOLUTIONS OF ORDINARY DIFFERENTIAL EQUATIONS (II)	1962	W. N. Everitt	8
+	Algorithm 810: The SLEIGN2 Sturm-Liouville Code	2001	Paul B. Bailey W. N. Everitt Anton Zettl	8
+	Differential Operators Generated by a Countable Number of Quasi-Differential Expressions on the Real Line	1992	W. N. Everitt Anton Zettl	8
+	Ramifications of Landau's inequality	1980	Man Kam Kwong Anton Zettl	8
+	Direct methods of qualitative spectral analysis of singular differential operators	1965	I. M. Glazman	8
+	On inequalities between the powers of a linear operator	1964	Ju. I. Ljubič	8
+	Dependence of Eigenvalues of Sturm–Liouville Problems on the Boundary	1996	Qingkai Kong Anton Zettl	8
+ PDF Chat	Polynomials and the limit point condition	1975	Robert M. Kauffman	8
+	The spectral theory of periodic differential equations	1973	M. S. P. Eastham	8