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Janne Heittokangas

Janne Heittokangas

University Lecturer

Department of Physics and Mathematics, Faculty of Science, Forestry and Technology

janne.heittokangas@uef.fi | +358 50 442 2381

0504422381
050 4422381
050 442 2381
+358 50 442 2381
+35850 442 2381
050 4422 381
+358 50 4422 381
+35850 4422 381
+358 50 4422381
+35850 4422381
+358504422381

Information Publications

Research groups

Complex Analysis 30.08.2018 -

Publications

59 items

A Continuous Transition from E-Sets to R-sets and Beyond
Ding, Jie; Heittokangas, Janne; Wen, Zhi-Tao. 2023. Journal of geometric analysis. 33: . 278
Asymptotic integration theory for f''+ P(z)f=0
Gundersen, Gary G.; Heittokangas, Janne; Zemirni, Mohamed Amine. 2022. Expositiones mathematicae. 40: 94-126
Description of growth and oscillation of solutions of complex LDE’s
Chyzhykov, Igor; Gröhn, Janne; Heittokangas, Janne; Rättyä, Jouni. 2022. Journal of the australian mathematical society. [Published online 16 June 2022]: 1-27
Irregular finite order solutions of complex LDE's in unit disc
Chyzhykov, Igor; Filevych, Petro; Gröhn, Janne; Heittokangas, Janne; Rättyä, Jouni. 2022. Journal de mathematiques pures et appliquees. 160: 158-201
Meromorphic Functions of Finite ϕ-order and Linear Askey—Wilson Divided Difference Equations
Yu, Hui; Heittokangas, Janne; Wang, Jun; Wen, Zhi Tao. 2022. Acta mathematica sinica : english series. 38: 371-383
Opiskelun joustavuuden lisääminen matematiikan yliopisto-opintojen taitekohdassa
Eronen Lasse; Heittokangas Janne. 2022. FMSERA Journal. 5: 61-75
Oscillation of Solutions of LDE’s in Domains Conformally Equivalent to Unit Disc
Chyzhykov, I.; Gröhn, J.; Heittokangas, J.; Rättyä, J.. 2022. Journal of geometric analysis. 32:
Value distribution of exponential polynomials and their role in the theories of complex differential equations and oscillation theory
Heittokangas, Janne; Ishizaki, Katsuya; Tohge, Kazuya; Wen, Zhi‐Tao. 2022. Bulletin of the london mathematical society. 2023; 55: 1-77
Contour integral solutions of linear differential equations which include a generalization of the Airy integral
Gundersen, Gary G; Heittokangas, Janne M; Wen, Zhi-Tao. 2021. Houston journal of mathematics. 47: 321–351
Dual exponential polynomials and a problem of Ozawa
Heittokangas, Janne; Ishizaki, Katsuya; Tohge, Kazuya; Wen, Zhi-Tao. 2021. Proceedings of the Royal Society of Edinburgh section A: mathematics. 152: 701-719
Meromorphic functions of finite φ-order and linear q-difference equations
Heittokangas, J; Wang, J; Wen, ZT; Yu, H. 2021. Journal of difference equations and applications. 27: 1280-1309
On Petrenko's deviations and second order differential equations
Heittokangas, Janne; Zemirni, Mohamed Amine. 2021. Kodai mathematical journal. 44: 181-193
On meromorphic solutions of non-linear differential equations of Tumura - Clunie type
Heittokangas, J; Latreuch, Z; Wang, J; Zemirni, M A. 2021. Mathematische nachrichten. 294: 748-773
On the limits of real-valued functions in sets involving Ψ-density, and applications
Heittokangas, Janne; Latreuch, Zinelaabidine; Wang, Jun; Zemirni, Amine. 2021. Journal of mathematical analysis and applications. 507: 125787
The asymptotic number of zeros of exponential sums in critical strips
Heittokangas, J; Wen, ZT. 2021. Monatshefte fur mathematik. 194: 261-273
Deficient Values of Solutions of Linear Differential Equations
Gundersen, Gary G; Heittokangas, Janne; Wen, Zhi-Tao. 2020. Computational methods and function theory. 2021; 21: 145-177
Exponential polynomials in the oscillation theory
Heittokangas, Janne; Ishizaki, Katsuya; Laine, Ilpo; Tohge, Kazuya. 2020. Journal of differential equations. 272: 911-937
Generalization of Pólya's Zero Distribution Theory for Exponential Polynomials, and Sharp Results for Asymptotic Growth
Heittokangas, Janne; Wen, Zhi-Tao. 2020. Computational methods and function theory. 2021; 21: 245-270
On the number of linearly independent admissible solutions to linear differential and linear difference equations
Heittokangas, Janne; Yu, Hui; Zemirni, Mohamed Amine. 2020. Canadian journal of mathematics-journal canadien de mathematiques. 2021; 73: 1556-1591
Complex oscillation and nonoscillation results
Heittokangas, Janne; Ishizaki, Katsuya; Laine, Ilpo; Tohge, Kazuya. 2019. Transactions of the american mathematical society. 372: 6161-6182
Zero distribution and division results for exponential polynomials
Heittokangas, Janne; Ishizaki, Katsuya; Tohge, Kazuya; Wen, Zhi-Tao. 2018. Israel journal of mathematics. 227: 397-421
Dual exponential polynomials and linear differential equations
Wen Zhi-Tao, Gundersen Gary G, Heittokangas Janne. 2017. Journal of differential equations. 2018; 264: 98-114
On the relationship between the lower order of coefficients and the growth of solutions of differential equations
Long Jianren, Heittokangas Janne, Ye Zhuan. 2016. Journal of mathematical analysis and applications. 444: 153-166
Completely regular growth solutions of second order complex linear differential equations
Heittokangas Janne, Laine Ilpo, Tohge Kazuya, Wen Zhi-Tao. 2015. Annales academiae scientiarum fennicae-mathematica. 40: 985-1003
Second-order complex linear differential equations with special functions or extremal functions as coefficients
Wu Xiubi, Long Jianren, Heittokangas Janne, Qiu Ke-e. 2015. Electronic journal of differential equations. 2015: 1-15
Functions of finite logarithmic order in the unit disc, Part I
Heittokangas Janne, Wen Zhi-Tao. 2014. Journal of mathematical analysis and applications. 415: 435-461
Functions of finite logarithmic order in the unit disc, Part II
Heittokangas Janne, Wen Zhi-Tao. 2014. Computational methods and function theory. -: 1-22
On alpha-Polynomial Regular Functions, with Applications to Ordinary Differential Equations
Fenton Peter, Gröhn Janne, Heittokangas Janne, Rossi John, Rättyä Jouni. 2014. Proceedings of the Edinburgh Mathematical Society. 57: 405-421
On the complexity of finding a necessary and sufficient condition for Blaschke-oscillatory equations
Heittokangas Janne, Reijonen Atte. 2014. Glasgow mathematical journal. -: 1-12
Zero separation results for solutions of second order linear differential equations
Chuaqui Martin, Gröhn Janne, Heittokangas Janne, Rättyä Jouni. 2013. Advances in mathematics. 245: 382-422
Blaschke Products and Their Applications
Grudsky Sergei, Shargorodsky Eugene, Gauthier Paul, Heittokangas Janne, Boivin Andre, Zhu Changzhong, Mashreghi Javad, Cima Joseph, Pfaltzgraff John, Kraus Daniela, Roth Oliver, Chyzhykov Igor, Skaskiv Severyn, Gluchoff Alan, Hartmann Frederick, Baribeau Line, Feichtinger Hans, Pap Margit, Martin Maria, Vukotic Dragan et al.. Teoksessa: Javad Mashreghi, Emmanuel Fricain(toim.) , 2012. A survey on Blaschke-oscillatory differential.... s. 43-98. Springer
Exponential polynomials as solutions of certain nonlinear difference equations
Wen Zhi Tao, Heittokangas Janne, Laine Ilpo. 2012. Acta mathematica sinica : english series. 28: 1295-1306
New Findings on the Bank-Sauer Approach in Oscillation Theory
Gröhn Janne, Heittokangas Janne. 2012. Constructive approximation. 35: 345-361
A unit disc analogue of the Bank-Laine conjecture does not hold
Heittokangas Janne, Tohge Kazuya. 2011. Annales academiae scientiarum fennicae-mathematica. 36: 341-351
On interpolating Blaschke products and Blaschke-oscillatory equations
Heittokangas Janne. 2011. Constructive approximation. 34: 1-21
Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc
Chuaqui Martin, Gröhn Janne, Heittokangas Janne, Rättyä Jouni. 2011. Abstract and applied analysis. 2011: -
Uniqueness of meromorphic functions sharing values with their shifts
Heittokangas J, Korhonen R, Laine I, Rieppo J. 2011. Complex variables and elliptic equations. 56: 81-92
Zero distribution of solutions of complex linear differential equations determines growth of solutions
Heittokangas Janne, Rättyä Jouni. 2011. Mathematische nachrichten. 284: 412-420
Sharp logarithmic derivative estimates with applications to ordinary differential equations in the unit disc
I. Chyzhykov, J. Heittokangas, J. Rättyä. 2010. Journal of the australian mathematical society. 88: 145-167
Finiteness of &phi: order of solutions of linear differential equations in the unit disc
I. Chyzhykov, J. Heittokangas, J. Rättyä. 2009. Journal d'analyse mathématique. 109: 163-198
Growth estimates for solutions of nonhomogeneous linear complex differential equations
Janne Heittokangas, Risto Korhonen ja Jouni Rättyä. 2009. Annales academiae scientiarum fennicae-mathematica. 34: 145-156
Value sharing results for shifts of meromorphic functions, and sufficient conditions for periodicity
J. Heittokangas, R. Korhonen, I. Laine, J. Rieppo, J. Zhang. 2009. Journal of mathematical analysis and applications. 355: 352-363
Linear differential equations with coefficients in weighted Bergman and Hardy spaces
Janne Heittokangas, Risto Korhonen, Jouni Rättyä. 2008. Transactions of the american mathematical society. 360: 1035-1055
Growth estimates for logarithmic derivatives of Blaschke products and of functions in the Nevanlinna class
Janne Heittokangas. 2007. Kodai Mathematical Journal. 30: 263-279
Linear differential equations with solutions in Dirichlet type subspace of the Hardy space
J. Heittokangas, R. Korhonen, J. Rättyä. 2007. Nagoya Mathematical Journal. 187: 91-113
Blaschke-oscillatory equations of the form f''+A(z)f=0
Janne Heittokangas. 2006. Journal of mathematical analysis and applications. 318: 120-133
Fast growing solutions of linear differential equations in the unit disc
Janne Heittokangas, Risto Korhonen, Jouni Rättyä. 2006. Results in mathematics. 49: 265-278
Solutions of f''+A(z)f=0 in the unit disc having Blaschke sequences as the zeros
Janne Heittokangas. 2005. Computational methods and function theory. 5: 49-63
Solutions of f''+A(z)f=0 with prescribed sequences of zeros
J. Heittokangas, I. Laine. 2005. Acta Mathematica Universitatis Comenianae. 74: 287-307
Generalized logarithmic derivative estimates of Gol'dberg-Grinshtein type
J. Heittokangas, R. Korhonen, J. Rättyä. 2004. Bulletin of the london mathematical society. 36: 105-114
Growth estimates for solutions of linear complex differential equations
J. Heittokangas, R. Korhonen, J. Rättyä. 2004. Annales academiae scientiarum fennicae-mathematica. 29: 233-246
Symposium on Complex Differential and Functional Equations
Rauno Aulaskari, Janne Heittokangas, Visa Latvala, Jari Taskinen (eds.). 2004. University of Joensuu, Department of Mathematics. Report Series. . Joensuun yliopisto
Linear differential equations and logarithmic derivative estimates
Igor Chyzhykov, Gary G. Gundersen, Janne Heittokangas. 2003. Proceedings of the london mathematical society. 86: 735-754
Meromorphic solutions of generalized Schröder equations
Gary G. Gundersen, Janne Heittokangas, Ilpo Laine, Jarkko Rieppo, Dequi Yang. 2002. Aequationes mathematicae. 63: 110-135
On meromorphic solutions of certain nonlinear differential equations
J. Heittokangas, R. Korhonen, I. Laine. 2002. Bulletin of the australian mathematical society. 66: 331-343
Complex difference equations of Malmquist type
Janne Heittokangas, Risto Korhonen, Ilpo Laine, Jarkko Rieppo, Katsuya Tohge. 2001. Computational methods and function theory. 1: 27-39
Differential equations with Hadamard products and Ruscheweyh derivatives
Janne Heittokangas. 2000. Mathematical Reports. 2(52): 467-484
Meromorphic solutions of some linear functional equations
Janne Heittokangas, Ilpo Laine, Jarkko Rieppo, Degui Yang. 2000. Aequationes mathematicae. 60: 148-166
On complex differential equations in the unit disc
Janne Heittokangas. 2000. Annales Academiae Scientiarum Fennicae. Mathematica. Dissertationes

University of Eastern Finland Joensuu, Kuopio © University of Eastern Finland

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Janne Heittokangas

Research groups

A Continuous Transition from E-Sets to R-sets and Beyond

Asymptotic integration theory for f''+ P(z)f=0

Description of growth and oscillation of solutions of complex LDE’s

Irregular finite order solutions of complex LDE's in unit disc

Meromorphic Functions of Finite ϕ-order and Linear Askey—Wilson Divided Difference Equations

Opiskelun joustavuuden lisääminen matematiikan yliopisto-opintojen taitekohdassa

Oscillation of Solutions of LDE’s in Domains Conformally Equivalent to Unit Disc

Value distribution of exponential polynomials and their role in the theories of complex differential equations and oscillation theory

Contour integral solutions of linear differential equations which include a generalization of the Airy integral

Dual exponential polynomials and a problem of Ozawa

Meromorphic functions of finite φ-order and linear q-difference equations

On Petrenko's deviations and second order differential equations

On meromorphic solutions of non-linear differential equations of Tumura - Clunie type

On the limits of real-valued functions in sets involving Ψ-density, and applications

The asymptotic number of zeros of exponential sums in critical strips

Deficient Values of Solutions of Linear Differential Equations

Exponential polynomials in the oscillation theory

Generalization of Pólya's Zero Distribution Theory for Exponential Polynomials, and Sharp Results for Asymptotic Growth

On the number of linearly independent admissible solutions to linear differential and linear difference equations

Complex oscillation and nonoscillation results

Zero distribution and division results for exponential polynomials

Dual exponential polynomials and linear differential equations

On the relationship between the lower order of coefficients and the growth of solutions of differential equations

Completely regular growth solutions of second order complex linear differential equations

Second-order complex linear differential equations with special functions or extremal functions as coefficients

Functions of finite logarithmic order in the unit disc, Part I

Functions of finite logarithmic order in the unit disc, Part II

On alpha-Polynomial Regular Functions, with Applications to Ordinary Differential Equations

On the complexity of finding a necessary and sufficient condition for Blaschke-oscillatory equations

Zero separation results for solutions of second order linear differential equations

Blaschke Products and Their Applications

Exponential polynomials as solutions of certain nonlinear difference equations

New Findings on the Bank-Sauer Approach in Oscillation Theory

A unit disc analogue of the Bank-Laine conjecture does not hold

On interpolating Blaschke products and Blaschke-oscillatory equations

Possible Intervals for T- and M-Orders of Solutions of Linear Differential Equations in the Unit Disc

Uniqueness of meromorphic functions sharing values with their shifts

Zero distribution of solutions of complex linear differential equations determines growth of solutions

Sharp logarithmic derivative estimates with applications to ordinary differential equations in the unit disc

Finiteness of &phi: order of solutions of linear differential equations in the unit disc

Growth estimates for solutions of nonhomogeneous linear complex differential equations

Value sharing results for shifts of meromorphic functions, and sufficient conditions for periodicity

Linear differential equations with coefficients in weighted Bergman and Hardy spaces

Growth estimates for logarithmic derivatives of Blaschke products and of functions in the Nevanlinna class

Linear differential equations with solutions in Dirichlet type subspace of the Hardy space

Blaschke-oscillatory equations of the form f''+A(z)f=0

Fast growing solutions of linear differential equations in the unit disc

Solutions of f''+A(z)f=0 in the unit disc having Blaschke sequences as the zeros

Solutions of f''+A(z)f=0 with prescribed sequences of zeros

Generalized logarithmic derivative estimates of Gol'dberg-Grinshtein type

Growth estimates for solutions of linear complex differential equations

Symposium on Complex Differential and Functional Equations

Linear differential equations and logarithmic derivative estimates

Meromorphic solutions of generalized Schröder equations

On meromorphic solutions of certain nonlinear differential equations

Complex difference equations of Malmquist type

Differential equations with Hadamard products and Ruscheweyh derivatives

Meromorphic solutions of some linear functional equations

On complex differential equations in the unit disc