Geodesic

Sommaire du Fascicule no. 1

Some problems of the type of the Bicadze--Samarski{\v\i} problem for a certain equation of mixed type
p. 3-6
Inverse problems for the transport equation
p. 7-17
A certain problem for an equation of mixed type with two parallel lines of degeneracy
p. 18-23
Determining the coefficient in a parabolic equation
p. 24-35
Analyticity of the solutions of Problem~$E$ for a certain degenerate elliptic equation
p. 36-40
The spectrum of a moment-free operator in the theory of thin shells of revolution
p. 41-52
Asymptotic behavior of the solution of the Cauchy problem for the two-dimensional system of equations of a rotating compressible fluid
p. 53-58
The Darboux problem for a certain degenerate equation
p. 59-68
A certain boundary value problem of Gevrey for a parabolic equation with a discontinuity of the first kind involving a change of sign in the coefficient of the time derivative
p. 69-77
A certain problem with nonlocal boundary conditions on the characteristics for an equation of mixed type
p. 78-88
The unique solvability of the Darboux problem for a certain degenerate system
p. 89-99
Inverse problems for degenerate equations, and Volterra integral equations of the third kind
p. 100-111
A solution of certain boundary value problems for generalized analytic functions
p. 112-116
Boundary value problems for a certain class of differential operators
p. 117-131
Boundary value problems for certain systems that can be reduced to elliptic systems
p. 132-142
Solution of a certain boundary value problem with shift in the theory of functions
p. 143-152
The solvability of the interior inverse problem for the logarithmic potential
p. 153-158
Boundary value problems for equations of composite type in unbounded domains
p. 159-161
Critical points of the Green's function for the exterior of a symmetric domain
p. 162-164
The uniqueness of the solution of certain inverse hyperbolic problems
p. 165-167
Inverse problems of logarithmic potential for the case of a body that is near a given one
p. 168-170
The $\zeta $-function in an elliptic Sobolev problem
p. 171-173
A certain boundary value problem for a system of harmonic functions
p. 174-177

Sommaire du Fascicule no. 2

The exceptional direction of an $n$th order system at a stationary point
p. 187-194
A qualitative study in the large of a certain class of dynamical systems
p. 195-201
The asymptotic behavior of the solutions of a second order equation under a confluence of singular points
p. 202-209
The oscillation of the solutions of nonlinear differential equations with deviating argument
p. 210-220
Two-sided difference schemes for the Sturm--Liouville problem
p. 221-230
The nontriviality of certain classes of functions, and the solvability of nonlinear ordinary differential equations of infinite order
p. 231-240
Controllability of a linear system with aftereffect
p. 241-245
Oscillation criteria, connected with averaging, for the solutions of second order ordinary differential equations
p. 246-252
Entire solutions of a certain nonlinear differential equation
p. 253-257
Certain properties of generalized $\phi$-invariant systems of linear differential equations
p. 258-264
Triangular and triangularizable differential systems
p. 265-269
The compatible recurrence of the bounded solutions of first order differential equations
p. 270-275
Expansion in the eigenfunctions of two pseudodifferential operators
p. 276-280
Smoothness with respect to part of the variables for solutions of linear partial differential equations
p. 281-289
Calculation of the values of a closed unbounded operator
p. 290-300
Problems of electrostatics in an inhomogeneous medium. The case of a thin dielectric with a large dielectric constant.~I
p. 301-309
Solution of the Cauchy problem for a certain nonstationary equation, and its asymptotic behavior for large time values.~I
p. 310-329
A certain method of solving spatial boundary value problems for a composite wedge
p. 330-334
On the question of asymptotic expansion of the solutions of the renewal equation
p. 335-341
The application of the method of Ju.\,D.~Sokolov to a certain singular integro-differential equation
p. 342-348
Minimization of nonsmooth functions on the set of finite states of a dynamical system
p. 349-350
A certain form of moving singularities of a system of two nonlinear equations
p. 351-354
The regularization of an explicit difference scheme of increased accuracy for the multidimensional heat equation
p. 355-357
Differential systems with $\phi$-solutions
p. 358-360
The continuability of the solutions of a functional-differential equation of neutral type
p. 361-363
A linear inhomogeneous equation on a Lie group
p. 364-366
Conditions for a center for the equation $P_3(x)yy'=\sum_{i=0}^2P_i(x)y^i$
p. 367-368

Sommaire du Fascicule no. 3

Analytic and qualitative theory, and also asymptotic behavior of the solutions of the system of equations $\frac{dx}{dz}=\frac1{z}\sqrt{xy(x+y)}$, $\frac{dy}{dz}=\frac1{1-z}\sqrt{xy(x+y)}$
p. 379-408
On the formulation of boundary value problems for differential equations with deviating argument and several highest terms
p. 409-418
On the controllability of systems with distributed lag
p. 419-425
A condition for the nonvanishing of the Wronskian of a fundamental system of solutions of a linear differential equation with retarded argument
p. 426-430
The cyclic trajectories of systems with switching
p. 431-435
A differential guidance game with integral constraints on the controls of the adversaries
p. 436-446
A stability analysis of resonance problems
p. 447-457
Application of the method of I.\,A.~Lappo-Danilevski{\v\i} to the problem of finding functions that map a half-plane conformally onto circular polygons
p. 458-469
The preservation of the nature of the recurrence of the solutions of differential equations under perturbations
p. 470-475
Asymptotic behavior of the limiting value of the Green's function of a pseudodifferential operator
p. 476-480
Conditions for the convergence of spectral decompositions that correspond to self-adjoint extensions of elliptic operators. V. A theorem on the uniform convergence of the spectral decomposition for a general second order elliptic operator
p. 481-506
Estimate of the change of the solution of the Dirichlet problem under variation of the domain
p. 507-512
On the problem of constructing a complete integral of the Hamilton--Jacobi equation
p. 513-520
On the question of an integral equation with deviating argument
p. 521-530
Controllable operators
p. 531-536
On the second theorem of N.\,N.~Bogoljubov in the averaging principle for functional-differential equations of neutral type
p. 537-540
The index and solvability of a certain problem for a singular integro-differential equation with conjugation
p. 541-543
The order of an algebraic curve that is a solution of a differential equation
p. 544-546
The limit cycles of a certain dynamical system
p. 547-549
Expansion in the eigenfunctions of a second order partial differential equation of polar type in the case of the whole plane
p. 550-552
The realizability of the phase diagrams of structurally stable three-dimensional dissipative systems
p. 553-554
A certain method of constructing integrable linear equations with a small parameter
p. 555-557
Holomorphic integrals of a certain system of differential equations
p. 558-560
The Cauchy problem for a stochastic first order hyperbolic system
p. 561-562
The radius of attraction of a certain two-dimensional system
p. 563-566
Family of periodic solutions of a system of second order differential equations without dissipation
p. 567-568
Поправки к~статье: ``Доказательство существования неправильных систем линейных
Поправки к~статье: ``Системы с~интегральной разделенностью всюду плотны в~множестве
Поправки к~статье: ``О~неустойчивости особых показателей и о~несимметричности

Sommaire du Fascicule no. 4

Linear boundary value problems for functional-differential equations
p. 579-584
Tests for the existence of the center, and its isochronism
p. 585-590
An analogue of Kelley's condition in optimal systems with lag
p. 591-597
Quasiregular synthesis
p. 598-605
The number of Ljapunov constants for the conditions of the center of a certain differential equation
p. 606-612
Coalition differential games
p. 613-623
Zeros of the eigenfunctions of a quasiperiodic problem
p. 624-628
On the theory of the complete controllability of linear systems with lag
p. 629-634
On the theory of bounded solutions of ordinary differential equations
p. 635-646
On the problem of isochronism for systems with discontinuous right-hand sides
p. 647-658
The stability of the singular exponents of a linear system, and the closure of the set of linear systems with exponential dichotomy.~I
p. 659-670
On the question of certain linearization methods
p. 671-675
Sequences of linear aggregates that consist of eigenfunctions of a differential operator
p. 676-686
A certain problem on the transversal oscillations of a composite rod
p. 687-698
A theorem on the coincidence of the classical solution of the Dirichlet problem for a nonselfadjoint elliptic equation with the generalized solution of this problem
p. 699-711
The zeros of polynomials of several variables
p. 712-720
Methods of solution of certain filtration problems
p. 721-729
Solution of the Cauchy problem for a certain nonstationary equation, and its asymptotic behavior for large time values.~II
p. 730-743
The localization of spectral expansions
p. 744-746
The exterior generalized Dirichlet problem for the Helmholtz equation
p. 747-750
A Sturm type comparison theorem for systems of fourth order ordinary differential equations
p. 751-754
Estimates of the solutions of the system $x''' =A(t)x$
p. 755-758
Boundary value problems for equations that contain in their principal part operators of the form $\frac{d^{2m+1}}{dt^{2m+1}}+A$
p. 759-762

Sommaire du Fascicule no. 5

A qualitative study in the large of a certain dynamical system with two algebraic integrals in the form of hyperbolas
p. 771-777
Uniqueness criteria for normal domains of the second type in $R^3$
p. 778-787
On methods of observing linear perturbable systems
p. 788-791
The existence and uniqueness of the solutions of boundary value problems for differential equations with deviating argument
p. 792-798
The stabilization of a linear system with compactly supported controls
p. 799-803
Monotone differential equations.~I
p. 804-815
Systems of Morse--Smale type with identical phase diagrams
p. 816-821
Questions of the isochronism of systems with discontinuous right hand sides
p. 822-837
A reduction theorem
p. 838-843
A certain method for the construction of acyclic and monocyclic domains
p. 844-850
The approximate solution of a two-point singular boundary value problem for a second-order ordinary differential equation
p. 851-859
Generation of periodic motions from an equilibrium state with purely imaginary roots
p. 860-872
The movable singularities of a certain class of differential equations
p. 873-878
Estimation of the growth of the eigenvalues of a certain problem with a parameter in the boundary condition
p. 879-889
A certain inverse problem for quasilinear parabolic equations
p. 890-898
Harnack's inequality for one-dimensional parabolic equations
p. 899-904
Certain estimates for the solutions of a quasilinear equation with small parameters
p. 905-918
The asymptotes of the solutions of finite difference equations
p. 919-925
The convergence of the differential-difference method in the solution of certain boundary value problems for multidimensional nonstationary equations of mathematical physics, and its realization
p. 926-932
The observability and identifiability of systems with lag
p. 933-935
The approximate solution of certain integro-differential equations
p. 936-939
A certain application of the method of fractional integration by parts
p. 940-942
Certain boundary value problems for strongly nonlinear second-order ordinary differential equations
p. 943-946
\"Uber Grenzzyklen einer quadratischen Differentialgleichung
p. 947-949
Boundary value problems for equations with operators of the form $\frac{d^{2m}}{dt^{2m}}+A$
p. 950-952

Sommaire du Fascicule no. 6

The analytic and the qualitative theory, and also the asymptotic behavior of the solutions of the system $dx/dz=2\surd P(x,y)/z$, $dy/dz=2$ $\surd P(x,y)/(1-z)$. I
p. 963-995
Certain properties of the generalized Green's matrices of linear differential operators
p. 996-1002
Controllability of linear systems with distributed lag in the control
p. 1003-1008
Conditions for the existence of the maximal number of polynomial solutions of differential equations
p. 1009-1014
The problems of Frommer
p. 1015-1024
The behavior of the solutions of a certain strongly nonlinear differential equation with retarded argument
p. 1025-1036
The asymptotic behavior of the solutions of certain systems with a small parameter multiplying the derivative
p. 1037-1049
An investigation of the second variation on singular controls
p. 1050-1066
Asymptotic behavior of the eigenvalues and eigenfunctions of the Sturm--Liouville operator with a complex-valued polynomial potential.~II
p. 1067-1073
A certain method of partial averaging in differential equations
p. 1074-1077
Stabilization of the solutions for a certain quasilinear parabolic system of equations in divergence form
p. 1078-1090
The form of the scattering operator for the system of Maxwell equations
p. 1091-1102
The asymptotically $\omega$-periodic solutions of Volterra integral equations
p. 1103-1110
The orthogonal expansion of a function of two arguments, and the solutions of certain equations
p. 1111-1116
An approximate method for solving a certain singular integro-differential equation
p. 1117-1123
Averaging in certain systems of integro-differential equations
p. 1124-1129
The connection between certain necessary conditions for the optimality of singular controls
p. 1130-1133
On the solution of the problem of the analytic design of regulators
p. 1134-1135
The oscillation of the solutions of linear equations
p. 1136-1138
Certain algorithms for the construction of higher approximations for systems of integro-differential equations
p. 1139-1141
Almost periodic solutions of second order hyperbolic equations
p. 1142-1144
III Всесоюзная конференция по качественной теории дифференциальных уравнений и ее применениям
p. 1145-1146

Sommaire du Fascicule no. 7

A certain boundary value problem
p. 1155-1159
The duality of the problems of optimal observation and control for linear systems with lag
p. 1160-1167
The behavior of the trajectories of a homogeneous system in the neighborhood of an invariant cone
p. 1168-1172
The marked trajectories of a quasiregular synthesis
p. 1173-1185
The computation of singular controls
p. 1186-1195
Qualitative study in the large of a certain dynamical system
p. 1196-1204
The solution of boundary value problems for differential equations of odd orders by means of branching continued fractions
p. 1205-1212
Minimax problems of optimal control
p. 1213-1224
Extensions of dynamical systems with uniformly asymptotically stable points
p. 1225-1230
Integral curves of the differential equation $(1+x)yy'=-x P_3(x)-x P_1(x)y+\delta y^2$ with a center
p. 1231-1241
An estimate of the oscillating solutions of a linear homogeneous system of differential equations with retarded argument
p. 1242-1247
Asymptotic expansion of the solution of the problem with initial jump for a system of nonlinear ordinary differential equations with a small parameter multiplying the highest derivative
p. 1248-1263
On the theory of differential equations with discontinuous right-hand sides
p. 1264-1275
The zeta-function and eigenvalues of differential operators
p. 1276-1285
A certain differential game with integral pay-off
p. 1286-1292
Quasiperiodic Green's functions for the Laplace and the Helmholtz equation
p. 1293-1297
A certain condition for the solvability of the Dirichlet problem
p. 1298-1302
Difference schemes for quasilinear nonstationary problems.~I
p. 1303-1311
Asymptotic behavior of the solution of a linear difference system with small difference in the presence of a ``turning point''
p. 1312-1321
On the theory of bifurcations of dynamical systems under a rotation of the field
p. 1322-1324
A mixed boundary value problem of the stationary theory of heat conduction for the half-plane with boundary condition of the third kind
p. 1325-1327
A theorem on the impossibility of a gradient catastrophe for a certain class of multidimensional systems of quasilinear equations
p. 1328-1331
The bifurcation of quasistationary periodic solutions of differential-difference equations
p. 1332-1334
An example of the inapplicability of the quasi-reversibility method to finding boundary functions that control the solution of the heat equation
p. 1335-1337

Sommaire du Fascicule no. 8

The normal solvability of the problem of the periodic solutions of a linear differential equation with deviating argument
p. 1347-1353
The integration of the Euler equations of the unperturbed motion of a rotating body
p. 1354-1365
Tests of the uniqueness of the $O$-curve for $N_2$ in $R^n$
p. 1366-1374
The hyperbolicity of the neighborhood of a homoclinic point
p. 1375-1378
Attainability of the estimate of the highest exponent in the freezing method in the case $n>2$
p. 1379-1386
Conditions for the conjugacy of the solutions of nonlinear ordinary differential equations.~I, II
p. 1387-1399
A note on the conjugacy of the solutions of higher order differential inequalities and equations with retarded argument
p. 1400-1405
The controllability in the small of systems of nonlinear differential equations of optimal regulation
p. 1406-1411
The approximate determination of the period of the periodic solution of a certain strongly nonlinear system
p. 1412-1422
A representation of the solutions of systems of linear functional-differential equations of neutral type
p. 1423-1429
Asymptotic behavior of the solution of certain problems with singular perturbations for systems of linear ordinary differential equations
p. 1430-1442
On the problem of the relative controllability of systems with deviating argument of neutral type
p. 1443-1450
The asymptotic solutions of certain systems of partial differential equations
p. 1451-1462
Fundamental solutions of parabolic systems with discontinuous coefficients, and their applications to boundary value problems.~I
p. 1463-1477
The global existence of a continuous solution of an initial-boundary value problem for a quasilinear first order equation
p. 1478-1485
The approximate solution of nonlinear singular integral equations by the Newton--Kantorovi{\v{c}} method
p. 1486-1490
An integrodifferential system of equations of reactor kinetics
p. 1491-1503
A two-point problem for indefinite integral equations
p. 1504-1508
A method of asymptotic integration of a certain class of integrodifferential equations with a small parameter multiplying the highest derivative
p. 1509-1519
Averaging of a certain special class of integrodifferential equations
p. 1520-1524
Elliptic operators that depend nonlinearly on a parameter
p. 1525-1526
Problems of the construction of comparison functions in the theory of the stability of motion
p. 1527-1529
Hyperbolic equations with multiple characteristics
p. 1530-1532
A qualitative study of a certain system of three differential equations by means of integral surfaces
p. 1533-1536

Sommaire du Fascicule no. 9

The comparison method in the dynamics of systems.~I, II
p. 1547-1559
The periodic solutions of second order systems
p. 1560-1564
A singularly perturbed boundary value problem with a degeneracy of the order of growth
p. 1565-1573
Certain properties of the relation of almost reducibility in a set of systems of linear differential equations
p. 1574-1585
Conditions for the conjugacy of the solutions of nonlinear ordinary differential equations.~I, II
p. 1586-1594
Diffeomorphisms of autonomous systems that contain a small parameter
p. 1595-1606
A certain evolution equation with degeneracy
p. 1607-1615
The optimal control of certain linear systems with aftereffect in the presence of random perturbations
p. 1616-1629
Optimal estimation of the interval of solvability of a multipoint boundary value problem
p. 1630-1641
Simultaneous attainability of the central exponents of $n$-dimensional diagonal systems
p. 1642-1651
Certain properties of systems of linear differential equations
p. 1652-1661
Stability of systems of neutral type with a countable number of transformations of the argument
p. 1662-1672
The asymptotic behavior of the spectrum of a differential operator in a space of vector-valued functions
p. 1673-1683
The first boundary value problem for elliptic equations in an unbounded domain
p. 1684-1691
The correct solvability of an extended boundary value problem for a parabolic equation
p. 1692-1698
The coercive solvability of fourth order difference equations
p. 1699-1713
Variational methods for solving equations
p. 1714-1720
Uniqueness and convergence of successive approximations for a certain class of Volterra equations
p. 1721-1724
An application of singular intergral equations to the solution of the first fundamental problem of thermoelasticity
p. 1725-1726
An $n$th order ordinary differential equation in a linear topological space
p. 1727-1729

Sommaire du Fascicule no. 10

The uniform stability of the characteristic exponents of a sequence of regular systems
p. 1739-1745
Integration of the Euler equations of the perturbed motion of a rotating body
p. 1746-1758
The maximum principle and the support principle in minimax problems of optimization
p. 1759-1771
The algebraic singularities of certain systems of differential equations
p. 1772-1777
A new method of investigation of the stability of the solutions of linear differential equations with nearly constant almost periodic coefficients
p. 1778-1788
Minimal number of inputs of linear control systems
p. 1789-1796
The stability of the singular exponents of a linear system, and the closure of the set of linear systems with exponential dichotomy.~II
p. 1797-1807
Traces with a weight, and the asymptotic behavior of the spectral function
p. 1808-1818
Some identities for the eigenvalues of a second order differential operator that has a point of swerve
p. 1819-1827
Asymptotic behavior of the solution of the Cauchy problem for a nonlinear system of ordinary differential equations with a small parameter multiplying the derivative
p. 1828-1838
Estimation of the solutions of spectral problems that correspond to problems for a parabolic equation of order greater than two
p. 1839-1848
Green's tensors in elasticity theory
p. 1849-1865
The solution of equations of the first kind with a closable operator
p. 1866-1871
Natural differential operators on manifolds, and boundary value problems that are elliptic in a subspace
p. 1872-1884
The behavior of the solutions of nonlinear equations with exponentially dichotomous linear part
p. 1885-1887
The invariance of the dicritical node of a multidimensional system
p. 1888-1890
A study of certain functional-differential equations with a regular singular point
p. 1891-1893
On the necessary optimality conditions for systems of neutral type
p. 1894-1897
An analytic construction of the guidance law that controls the rotational motion of a rigid body under indirect guidance
p. 1898-1899
Integration in closed form and asymptotic behavior of the solutions of third order linear ordinary differential equations
p. 1900-1904
The fundamental solution of quadratic systems of pseudodifferential equations
p. 1905-1907
The estimation of the solutions of a certain system of differential equations with a small parameter
p. 1908-1910
A certain property of nonlinear integral equations of Volterra type
p. 1911-1913

Sommaire du Fascicule no. 11

Periodic solutions of systems of autonomous functional-differential equations of neutral type with small lag
p. 1923-1931
Interior boundary layer in a boundary value problem with a degeneracy in the order of growth
p. 1932-1938
The asymptotic behavior of the spectrum of the Schr\"odinger operator
p. 1939-1945
Control of the spectrum of differential equations
p. 1946-1952
Asymptotic behavior of the solutions of linear systems of differential equations with deviating argument
p. 1953-1956
Conditions of disconjugacy for a linear homogeneous differential equation with retarded argument
p. 1957-1963
The analytic and the qualilative theory, and also the asymptotic behavior of the solutions of the system $dx/dz=2$ $\surd P(x,\,y)/z$. $dy/dz=2$ $\surd P(x,\,y)/(1-z)$. II
p. 1964-1987
The existence of the solutions of a system of functional equations of superneutral type with iterated lag
p. 1988-1992
Preservation of the property of stability in the presence of two zero roots and a line of equilibrium
p. 1993-2000
N. N. Bogoljubov's second theorem for systems of differential equations with impulse action
p. 2001-2009
Asymptotic behavior of the discrete spectrum of one-dimensional singular differential operators
p. 2010-2020
The Cauchy problem for evolution functional equations
p. 2021-2028
Meromorphic continuation of the scattering operator for Maxwell's system of equations
p. 2029-2041
An application of the method of averaging to a certain two-point boundary value problem for systems of integrodifferential equations of Fredholm type
p. 2042-2047
Continuous solutions of integral inclusions
p. 2048-2055
The global stability of a certain dissipative system
On the theory of successive approximations
p. 2057-2058
Coercive solvability of general boundary value problems for second order elliptic differential equations in a Banach space
p. 2059-2061
Application of the Newton-Kantorovi{\v{c}} method to the solution of nonlinear singular integro-differential equations with a Hilbert kernel
p. 2062-2063
On the question of the disconjugacy of second order singular linear differential equations
p. 2064-2067
The transcendental movable singular points of certain systems of differential equations
p. 2068-2070
Periodic solutions and the dissipativity of certain systems of differential equations
p. 2071-2072
A remark on a certain specifically nonlinear oscillation theorem
p. 2073-2074
The continuation of the solutions of multidimensional differential equations
p. 2075-2076
A certain class of differential equations with a limit cycle
p. 2077-2078
Holomorphic solutions of a certain class of Volterra integral equations
p. 2079-2080

Sommaire du Fascicule no. 12

On the question of the stability of the solutions of differential equations with retarded argument
p. 2091-2100
Anisotropic relativism
p. 2101-2110
Affine classification of a quadratic system
p. 2111-2124
Simultaneous attainability of central exponents
p. 2125-2136
A boundary value problem for second order quasilinear differential equations in divergence form with deviating argument
p. 2137-2146
Certain nonlinear two-point boundary value problems
p. 2147-2161
Programmed control from incomplete data
p. 2162-2172
An alternating integral in linear differential games with nonlinear controls
p. 2173-2178
A system of differential equations that has an infinite number of stable periodic solutions
p. 2179-2183
On the theory of equations of mixed type in multidimensional domains
p. 2184-2191
The symbolic method of solving boundary value and initial value problems for linear operator equations
p. 2192-2207
The asymptotic behavior of the solution of a certain Cauchy problem
p. 2208-2222
Functions whose limit values are trigonometric polynomials
p. 2223-2241
Solution of certain problems of the theory of oscillation of shells
p. 2242-2261
The asymptotics of an a posteriori error estimate of the difference solution of an ordinary differential equation
p. 2262-2266
The asymptotic behavior of the solutions of finite difference equations. I.~General statements
p. 2267-2278
The value of the regularization parameter in ill-posed control problems
p. 2279-2285
The control of manipulators
p. 2286-2287
The property of being Noetherian of the general boundary value problem for a linear functional differential equation
p. 2288-2291
A remark on the Nemycki{\v\i}--Bebutov theorem on completely unstable dynamical systems
p. 2292-2293
A generalization of the theorem of M.\,V.~Keldy{\v s} on the completeness of the eigen- and associated functions of the first boundary value problem for a nonselfadjoint elliptic operator
p. 2294-2296