Czesław Olech
Encyclopedia
Czesław Olech is a Polish mathematician. He is a representative of the Kraków school of mathematics
, especially the differential equation
s school of Tadeusz Ważewski
.
in Kraków
, obtained his doctorate at the Institute of Mathematical Sciences in 1958, habilitation in 1962, the title of associate professor in 1966, and the title of professor in 1973.
Czeslaw Olech, often as a visiting professor, was invited by the world's leading mathematical centers in the United States, USSR (later Russia), Canada and many European countries. He cooperated with Solomon Lefschetz
, Sergey Nikolsky, Philip Hartman and Roberto Conti, the most distinguished mathematicians involved in the theory of differential equations. Professor S. Lefschetz highly valued prof. Ważewski's school, and especially the retract method, which prof. Olech applied by developing, among other things, control theory
. He supervised nine doctoral dissertations, and reviewed a number of doctoral theses and dissertations.
Membership of:
Awards and honours:
Kraków School of Mathematics
Kraków School of Mathematics was a sub-group of Polish School of Mathematics represented by mathematicians from the Kraków universities—Jagiellonian University and the AGH University of Science and Technology, active during the interwar period...
, especially the differential equation
Differential equation
A differential equation is a mathematical equation for an unknown function of one or several variables that relates the values of the function itself and its derivatives of various orders...
s school of Tadeusz Ważewski
Tadeusz Wazewski
Tadeusz Ważewski was a Polish mathematician.Ważewski made important contributions to the theory of ordinary differential equations, partial differential equations, control theory and the theory of analytic spaces...
.
Education and career
In 1954 he completed his mathematical studies at the Jagiellonian UniversityJagiellonian University
The Jagiellonian University was established in 1364 by Casimir III the Great in Kazimierz . It is the oldest university in Poland, the second oldest university in Central Europe and one of the oldest universities in the world....
in Kraków
Kraków
Kraków also Krakow, or Cracow , is the second largest and one of the oldest cities in Poland. Situated on the Vistula River in the Lesser Poland region, the city dates back to the 7th century. Kraków has traditionally been one of the leading centres of Polish academic, cultural, and artistic life...
, obtained his doctorate at the Institute of Mathematical Sciences in 1958, habilitation in 1962, the title of associate professor in 1966, and the title of professor in 1973.
- 1970-1986: director of The Institute of Mathematics, Polish Academy of SciencesPolish Academy of SciencesThe Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
. - 1972-1991: director of Stefan Banach International Mathematical Center in WarsawWarsawWarsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...
. - 1979-1986: member of the Executive Committee, International Mathematical UnionInternational Mathematical UnionThe International Mathematical Union is an international non-governmental organisation devoted to international cooperation in the field of mathematics across the world. It is a member of the International Council for Science and supports the International Congress of Mathematicians...
. - 1982-1983: president of the Organizing Committee, International Congress of MathematiciansInternational Congress of MathematiciansThe International Congress of Mathematicians is the largest conference for the topic of mathematics. It meets once every four years, hosted by the International Mathematical Union ....
in WarsawWarsawWarsaw is the capital and largest city of Poland. It is located on the Vistula River, roughly from the Baltic Sea and from the Carpathian Mountains. Its population in 2010 was estimated at 1,716,855 residents with a greater metropolitan area of 2,631,902 residents, making Warsaw the 10th most...
, - 1987-1989: president of the Board of Mathematics, Polish Academy of SciencesPolish Academy of SciencesThe Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
. - 1990-2002: president of the Scientific Council, Institute of Mathematics of the Polish Academy of SciencesPolish Academy of SciencesThe Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
.
Czeslaw Olech, often as a visiting professor, was invited by the world's leading mathematical centers in the United States, USSR (later Russia), Canada and many European countries. He cooperated with Solomon Lefschetz
Solomon Lefschetz
Solomon Lefschetz was an American mathematician who did fundamental work on algebraic topology, its applications to algebraic geometry, and the theory of non-linear ordinary differential equations.-Life:...
, Sergey Nikolsky, Philip Hartman and Roberto Conti, the most distinguished mathematicians involved in the theory of differential equations. Professor S. Lefschetz highly valued prof. Ważewski's school, and especially the retract method, which prof. Olech applied by developing, among other things, control theory
Control theory
Control theory is an interdisciplinary branch of engineering and mathematics that deals with the behavior of dynamical systems. The desired output of a system is called the reference...
. He supervised nine doctoral dissertations, and reviewed a number of doctoral theses and dissertations.
Main fields of research interest
- Contributions to ordinary differential equations:
- various applications of Tadeusz WażewskiTadeusz WazewskiTadeusz Ważewski was a Polish mathematician.Ważewski made important contributions to the theory of ordinary differential equations, partial differential equations, control theory and the theory of analytic spaces...
topological method in studying asymptotic behaviourAsymptotic analysisIn mathematical analysis, asymptotic analysis is a method of describing limiting behavior. The methodology has applications across science. Examples are...
of solutions; - exact estimates of exponential growth of solution of second-order linear differential equationLinear differential equationLinear differential equations are of the formwhere the differential operator L is a linear operator, y is the unknown function , and the right hand side ƒ is a given function of the same nature as y...
s with bounded coefficients; - theoremTheoremIn mathematics, a theorem is a statement that has been proven on the basis of previously established statements, such as other theorems, and previously accepted statements, such as axioms...
s concerning global asymptotic stabilityLyapunov stabilityVarious types of stability may be discussed for the solutions of differential equations describing dynamical systems. The most important type is that concerning the stability of solutions near to a point of equilibrium. This may be discussed by the theory of Lyapunov...
of the autonomous system on the plane with stable Jacobian matrix at each point of the plane, results establishing relation between question of global asymptotic stability of an autonomous system and that of global one-to-oneness of a differentiable map; - contribution to the question whether unicity condition implies convergence of successive approximation to solutions of ordinary differential equations.
- various applications of Tadeusz Ważewski
- Contribution to optimal control theoryControl theoryControl theory is an interdisciplinary branch of engineering and mathematics that deals with the behavior of dynamical systems. The desired output of a system is called the reference...
:- establishing a most general version of the so-called bang-bangBang-bang controlIn control theory, a bang–bang controller , also known as a hysteresis controller, is a feedback controller that switches abruptly between two states. These controllers may be realized in terms of any element that provides hysteresis...
principle for linear control problem by detailed study of the integral of set valued map; - existence theoremTheoremIn mathematics, a theorem is a statement that has been proven on the basis of previously established statements, such as other theorems, and previously accepted statements, such as axioms...
s for optimal controlOptimal controlOptimal control theory, an extension of the calculus of variations, is a mathematical optimization method for deriving control policies. The method is largely due to the work of Lev Pontryagin and his collaborators in the Soviet Union and Richard Bellman in the United States.-General method:Optimal...
problem with unbounded controls and multidimensional cost functions; - existence of solution of differential inclusions with nonconvex right-hand side;
- characterization of controllability of convex processes.
- establishing a most general version of the so-called bang-bang
Recognition
Honorary doctorates:- Vilnius UniversityVilnius UniversityVilnius University is the oldest university in the Baltic states and one of the oldest in Eastern Europe. It is also the largest university in Lithuania....
1989 - Jagiellonian UniversityJagiellonian UniversityThe Jagiellonian University was established in 1364 by Casimir III the Great in Kazimierz . It is the oldest university in Poland, the second oldest university in Central Europe and one of the oldest universities in the world....
in KrakówKrakówKraków also Krakow, or Cracow , is the second largest and one of the oldest cities in Poland. Situated on the Vistula River in the Lesser Poland region, the city dates back to the 7th century. Kraków has traditionally been one of the leading centres of Polish academic, cultural, and artistic life...
2006 - AGH University of Science and TechnologyAGH University of Science and TechnologyAGH University of Science and Technology is the second largest technical university in Poland, located in Kraków. The university was established in 1919, and was formerly known as the University of Mining and Metallurgy...
in KrakówKrakówKraków also Krakow, or Cracow , is the second largest and one of the oldest cities in Poland. Situated on the Vistula River in the Lesser Poland region, the city dates back to the 7th century. Kraków has traditionally been one of the leading centres of Polish academic, cultural, and artistic life...
2009.
Membership of:
- PAN Polish Academy of SciencesPolish Academy of SciencesThe Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
(member of the Presidium), - PAU Polish Academy of Arts and SciencesPolish Academy of LearningThe Polish Academy of Arts and Sciences or Polish Academy of Learning , headquartered in Kraków, is one of two institutions in contemporary Poland having the nature of an academy of sciences....
- Pontifical Academy of SciencesPontifical Academy of SciencesThe Pontifical Academy of Sciences is a scientific academy of the Vatican, founded in 1936 by Pope Pius XI. It is placed under the protection of the reigning Supreme Pontiff. Its aim is to promote the progress of the mathematical, physical and natural sciences and the study of related...
- Russian Academy of SciencesRussian Academy of SciencesThe Russian Academy of Sciences consists of the national academy of Russia and a network of scientific research institutes from across the Russian Federation as well as auxiliary scientific and social units like libraries, publishers and hospitals....
- Polish Mathematical SocietyPolish Mathematical SocietyThe Polish Mathematical Society began in Kraków, Poland in 1917. It was originally simply called the Mathematical Society. It was officially constituted on April 2, 1919.Hugo Steinhaus, Stefan Banach and Otto Nikodym were among the founders....
- European Mathematical SocietyEuropean Mathematical SocietyThe European Mathematical Society is a European organization dedicated to the development of mathematics in Europe. Its members are different mathematical societies in Europe, academic institutions and individual mathematicians...
- American Mathematical SocietyAmerican Mathematical SocietyThe American Mathematical Society is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, which it does with various publications and conferences as well as annual monetary awards and prizes to mathematicians.The society is one of the...
Awards and honours:
- State Prize of Poland 1st Class
- The Commander's Cross of the Order of Polonia Restituta
- Marin DrinovMarin DrinovProfessor Marin Stoyanov Drinov was a Bulgarian historian and philologist from the National Revival period who lived and worked in Russia through most of his life...
Golden Medal, Bulgarian Academy of SciencesBulgarian Academy of SciencesThe Bulgarian Academy of Sciences is the National Academy of Bulgaria, established in 1869. The Academy is autonomous and has a Society of Academicians, Correspondent Members and Foreign Members... - Bernard BolzanoBernard BolzanoBernhard Placidus Johann Nepomuk Bolzano , Bernard Bolzano in English, was a Bohemian mathematician, logician, philosopher, theologian, Catholic priest and antimilitarist of German mother tongue.-Family:Bolzano was the son of two pious Catholics...
Golden Medal, Czechoslovak Academy of SciencesCzechoslovak Academy of SciencesThe Czechoslovak Academy of Sciences was established in 1953 to be the scientific center for Czechoslovakia. It was succeeded by the Academy of Sciences of the Czech Republic in 1992.-History:... - Stefan Banach Medal, Polish Academy of SciencesPolish Academy of SciencesThe Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
- Mikołaj KopernikNicolaus CopernicusNicolaus Copernicus was a Renaissance astronomer and the first person to formulate a comprehensive heliocentric cosmology which displaced the Earth from the center of the universe....
Medal, Polish Academy of SciencesPolish Academy of SciencesThe Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
Publications
- A talk on the occasion of receiving an honorary degree. (Polish) Wiadom. Mat. 42 (2006), 55—58.
- On the Ważewski equation. Proceedings of the Conference Topological Methods in Differential Equations and Dynamical Systems (Kraków-Przegorzaƚy, 1996). Univ. Iagel. Acta Math. No. 36 (1998), 55—64.
- My contacts with Professor Kuratowski, 1970--1980. (Polish) X School of the history of mathematics (Międzyzdroje, 1996). Zesz. Nauk. Uniw. Opol. Mat. 30 (1997), 109—114.
- with Janas, J. ; Szafraniec, F. H. Wƚodzimierz Mlak (1931--1994). Volume dedicated to the memory of Wƚodzimierz Mlak. Ann. Polon. Math. 66 (1997), 1--9.
- with Meisters, Gary H. Global stability, injectivity, and the Jacobian conjecture. World Congress of Nonlinear Analysts '92, Vol. I--IV (Tampa, FL, 1992), 1059—1072, de Gruyter, Berlin, 1996.
- with Meisters, Gary H. Power-exact, nilpotent, homogeneous matrices. Linear and Multilinear Algebra 35 (1993), no. 3-4, 225—236.
- Introduction. New directions in differential equations and dynamical systems, viii—x, Royal Soc. Edinburgh, Edinburgh, 1991.
- with Meisters, Gary H. Strong nilpotence holds in dimensions up to five only. Linear and Multilinear Algebra 30 (1991), no. 4, 231—255.
- with Parthasarathy, T. ; Ravindran, G. Almost N-matrices and linear complementarity. Linear Algebra Appl. 145 (1991), 107—125.
- with Parthasarathy, T. ; Ravindran, G. A class of globally univalent differentiable mappings. Arch. Math. (Brno) 26 (1990), no. 2-3, 165—172.
- with Meisters, Gary H. A Jacobian condition for injectivity of differentiable plane maps. Ann. Polon. Math. 51 (1990), 249—254.
- with Lasota, A. Zdzisƚaw Opial---a mathematician (1930--1974). Ann. Polon. Math. 51 (1990), 7--13.
- The Lyapunov theorem: its extensions and applications. Methods of nonconvex analysis (Varenna, 1989), 84—103, Lecture Notes in Math., 1446, Springer, Berlin, 1990.
- Global diffeomorphism question and differential equations. Qualitative theory of differential equations (Szeged, 1988), 465—471, Colloq. Math. Soc. János Bolyai, 53, North-Holland, Amsterdam, 1990.
- with Meisters, Gary H. Solution of the global asymptotic stability Jacobian conjecture for the polynomial case. Analyse mathématique et applications, 373—381, Gauthier-Villars, Montrouge, 1988.
- with Meisters, Gary H. A poly-flow formulation of the Jacobian conjecture. Bull. Polish Acad. Sci. Math. 35 (1987), no. 11-12, 725—731.
- Global asymptotic stability and global univalence on the plane. Proceedings of the Eleventh International Conference on Nonlinear Oscillations (Budapest, 1987), 189—194, János Bolyai Math. Soc., Budapest, 1987.
- Some remarks concerning controllability. Contributions to modern calculus of variations (Bologna, 1985), 184—188, Pitman Res. Notes Math. Ser., 148, Longman Sci. Tech., Harlow, 1987.
- On n-dimensional extensions of Fatou's lemma. Z. Angew. Math. Phys. 38 (1987), no. 2, 266—272.
- with Aubin, Jean-Pierre ; Frankowska, Halina. Controllability of convex processes. SIAM J. Control Optim. 24 (1986), no. 6, 1192—1211.
- with Meisters, Gary H. Global asymptotic stability for plane polynomial flows. Časopis Pěst. Mat. 111 (1986), no. 2, 123—126.
- with Aubin, Jean-Pierre ; Frankowska, Halina. Contrôlabilité des processus convexes[Controllability of convex processes]. C. R. Acad. Sci. Paris Sér. I Math. 301 (1985), no. 5, 153—156.
- Decomposability as a substitute for convexity. Multifunctions and integrands (Catania, 1983), 193—205, Lecture Notes in Math., 1091, Springer, Berlin, 1984.
- with Frankowska, Halina. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJ2-4KBD59R-2&_user=10&_coverDate=05%2F31%2F1982&_alid=1740330298&_rdoc=3&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=6866&_sort=r&_st=13&_docanchor=&view=c&_ct=38&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b901ca2ff0b265d9a45449cedc87fa93&searchtype=aBoundary solutions of differential inclusion. Special issue dedicated to J. P. LaSalle.] J. Differential Equations 44 (1982), no. 2, 156—165.
- with Frankowska, Halina. R-convexity of the integral of set-valued functions. Contributions to analysis and geometry (Baltimore, Md., 1980), pp. 117–129, Johns Hopkins Univ. Press, Baltimore, Md., 1981.
- Lower semiconductivity of integral functionals. Analysis and control of systems (IRIA Sem., Rocquencourt, 1978), pp. 109–117, IRIA, Rocquencourt, 1978.
- Differential games of evasion. Differential equations (Proc. Internat. Conf., Uppsala, 1977), pp. 155–161. Sympos. Univ. Upsaliensis Ann. Quingentesimum Celebrantis, No. 7, Almqvist & Wiksell, Stockholm, 1977.
- A characterization of L\sb{1}-weak lower semicontinuity of integral functionals. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 25 (1977), no. 2, 135—142.
- Existence theory in optimal control. Control theory and topics in functional analysis (Internat. Sem., Internat. Centre Theoret. Phys., Trieste, 1974), Vol. I, pp. 291–328. Internat. Atomic Energy Agency, Vienna, 1976.
- The achievements of Tadeusz Ważewski in the mathematical theory of optimal control. (Polish) Wiadom. Mat. (2) 20 (1976), no. 1, 66—69. 49-03
- with Szarski, J. ; Szmydt, Z. Tadeusz Ważewski (1896--1972). (Polish) Wiadom. Mat. (2) 20 (1976), no. 1, 55—62.
- Weak lower semicontinuity of integral functionals. Existence theorem issue. J. Optimization Theory Appl. 19 (1976), no. 1, 3--16.
- Existence theory in optimal control problems in the underlying ideas. International Conference on Differential Equations (Proc., Univ. Southern California, Los Angeles, Calif., 1974), pp. 612–635. Academic Press, New York, 1975.
- Existence of solutions of non-convex orientor fields. Collection of articles dedicated to Giovanni Sansone on the occasion of his eighty-fifth birthday. Boll. Un. Mat. Ital. (4) 11 (1975), no. 3, suppl., 189—197.
- The characterization of the weak closure of certain sets of integrable functions. Collection of articles dedicated to the memory of Lucien W. Neustadt. SIAM J. Control 12 (1974), 311—318.
- with Kaczyński, H. Existence of solutions of orientor fields with non-convex right-hand side. Collection of articles dedicated to the memory of Tadeusz Ważewski. Ann. Polon. Math. 29 (1974), 61—66.
- with Szarski, J. ; Szmydt, Z. Tadeusz Ważewski (1896--1972). Collection of articles dedicated to the memory of Tadeusz Ważewski. Ann. Polon. Math. 29 (1974), 1--13.
- with Węgrzyn, S. ; Skowronek, M. Optimization of a sequence of operations at limitations imposed on particular operations. Bull. Acad. Polon. Sci. Sér. Sci. Tech. 20 (1972), 65—68.
- Convexity in existence theory of optimal solution. Actes du Congrès International des Mathématiciens (Nice, 1970), Tome 3, pp. 187–192. Gauthier-Villars, Paris, 1971.
- with Węgrzyn, Stefan ; Skowronek, Marcin. Optimization of sequences of operations under constraints on the individual operations. (Polish) Podstawy Sterowania 1 (1971), 147—151.
- http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJ2-4CRM6GH-1P&_user=10&_coverDate=11%2F30%2F1969&_alid=1740330298&_rdoc=9&_fmt=high&_orig=search&_origin=search&_zone=rslt_list_item&_cdi=6866&_sort=r&_st=13&_docanchor=&view=c&_ct=38&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=f90df2f9a86e6e6c8982491679a47d3e&searchtype=aExistence theorems for optimal control problems involving multiple integrals]. J. Differential Equations 6 1969 512—526.
- Existence theorems for optimal problems with vector-valued cost function. Trans. Amer. Math. Soc. 136 1969 159—180.
- with Lasota, A. On Cesari's semicontinuity condition for set valued mappings. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 16 1968 711—716.
- On the range of an unbounded vector-valued measure. Math. Systems Theory 2 1968 251—256.
- On Approximation of set-valued functions by continuous functions. Colloq. Math. 19 1968 285—293.
- with Szegë, G. P. ; Cellina, A. On the stability properties of a third order system. Ann. Mat. Pura Appl. (4) 78 1968 91—103.
- Lexicographical order, range of integrals and "bang-bang" principle. 1967 Mathematical Theory of Control (Proc. Conf., Los Angeles, Calif., 1967) pp. 35–45 Academic Press, New York
- with Klee, Victor. Characterizations of a class of convex sets. Math. Scand 20 1967 290—296.
- with Pliś, A. Monotonicity assumption in uniqueness criteria for differential equations. Colloq. Math. 18 1967 43—58.
- On a system of integral inequalities. Colloq. Math. 16 1967 137—139.
- with Lasota, A. On the closedness of the set of trajectories of a control system. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 14 1966 615—621.
- with Lasota, A. An optimal solution of Nicoletti's boundary value problem. Ann. Polon. Math. 18 1966 131—139.
- Extremal solutions of a control system. J. Differential Equations 2 1966 74—101.
- Contribution to the time optimal control problem. Abh. Deutsch. Akad. Wiss. Berlin Kl. Math. Phys. Tech. 1965 1965 no. 2, 438—446 (1966).
- A note concerning set-valued measurable functions. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 13 1965 317—321.
- A note concerning extremal points of a convex set. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 13 1965 347—351.
- Global phase-portrait of a plane autonomous system. Ann. Inst. Fourier (Grenoble) 14 1964 fasc. 1, 87—97.
- with Mlak, W. Integration of infinite systems of differential inequalities. Ann. Polon. Math. 13 1963 105—112.
- On the global stability of an autonomous system on the plane. Contributions to Differential Equations 1 1963 389—400.
- with Meisters, Gary H. Locally one-to-one mappings and a classical theorem on schlicht functions. Duke Math. J. 30 1963 63—80.
- with Hartman, Philip. On global asymptotic stability of solutions of differential equations. Trans. Amer. Math. Soc. 104 1962 154—178.
- A connection between two certain methods of successive approximations in differential equations. Ann. Polon. Math. 11 1962 237—245.
- On the asymptotic coincidence of sets filled up by integrals of two systems of ordinary differential equations. Ann. Polon. Math. 11 1961 49—74.
- On the existence and uniqueness of solutions of an ordinary differential equation in the case of Banach space. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 8 1960 667—673.
- Remarks concerning criteria for uniqueness of solutions of ordinary differential equations. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 8 1960 661—666.
- A simple proof of a certain result of Z. Opial. Ann. Polon. Math. 8 1960 61—63.
- with Opial, Z. Sur une inégalité différentielle. (Italian) Ann. Polon. Math. 7 1960 247—254.
- Estimates of the exponential growth of solutions of a second order ordinary differential equation. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astr. Phys. 7 1959 487—494 (unbound insert).
- Periodic solutions of a system of two ordinary differential equations. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astr. Phys. 7 1959 137—140.
- Asymptotic behaviour of the solutions of second order differential equations. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astr. Phys. 7 1959 319—326 (unbound insert).
- On the characteristic exponents of the second order linear ordinary differential equation. Bull. Acad. Polon. Sci. Sér. Sci. Math. Astr. Phys. 6 1958 573—579.
- Sur un problème de M. G. Sansone lié à la théorie du synchrotrone. (French) Ann. Mat. Pura Appl. (4) 44 1957 317—329.
- On surfaces filled up by asymptotic integrals of a system of ordinary differential equations. Bull. Acad. Polon. Sci. Cl. III. 5 (1957), 935—941, LXXIX.
- with Opial, Z. ; Ważewski, T. Sur le problème d'oscillation des intégrales de l'équation y"+g(t)y=0. (French) Bull. Acad. Polon. Sci. Cl. III. 5 (1957), 621—626, LIII.
- Sur certaines propriétés des intégrales de l'équation y'=f(x,y), dont le second membre est doublement périodique. (French) Ann. Polon. Math. 3 (1957), 189—199.
- On the asymptotic behaviour of the solutions of a system of ordinary non-linear differential equations. Bull. Acad. Polon. Sci. Cl. III. 4 (1956), 555—561.
- with Gołąb, S. Contribution à la théorie de la formule simpsonienne des quadratures approchées. (French) Ann. Polon. Math. 1, (1954). 176—183.