It would help if there was a little bit more information about "these".
Poisson's equation is a partial differential equation of elliptic type. it is used in electrostatics, mechanical engineering and theoretical physics.
Maxwell's equations contain two scalar equations and two vector equations. Gauss' law and Gauss' law for magnetism are the scalar equations. The Maxwell-Faraday equation and Ampere's circuital law are the vector equations.
There is no quadratic equation that is 'linear'. There are linear equations and quadratic equations. Linear equations are equations in which the degree of the variable is 1, and quadratic equations are those equations in which the degree of the variable is 2.
An "inconsistent" set of equations. If they are all linear equations then the matrix of coefficients is singular.
Lars Garding has written: 'Cauchy's problem for hyperbolic equations' -- subject(s): Differential equations, Partial, Exponential functions, Partial Differential equations 'Applications of the theory of direct integrals of Hilbert spaces to some integral and differential operators' -- subject(s): Differential equations, Partial, Hilbert space, Partial Differential equations
Bernard Friedman has written: 'Techniques in solving partial differential equations' -- subject(s): Partial Differential equations 'Lectures on applications-oriented mathematics' -- subject(s): Mathematics
Jianhong Wu has written: 'Theory and applications of partial functional differential equations' -- subject(s): Functional differential equations
David L. Colton has written: 'Analytic theory of partial differential equations' -- subject(s): Differential equations, Partial, Numerical solutions, Partial Differential equations 'Partial differential equations' -- subject(s): Differential equations, Partial, Partial Differential equations
Fritz John has written: 'Partial differential equations, 1952-1953' -- subject(s): Differential equations, Partial, Partial Differential equations 'Fritz John collected papers' 'Partial differential equations' 'On finite deformations of an elastic material' 'Plane waves and spherical means applied to partial differential equations' -- subject(s): Differential equations, Partial, Partial Differential equations 'On behavior of solutions of partial differential equations'
George Francis Denton Duff has written: 'Partial differential equations' -- subject(s): Differential equations, Partial, Partial Differential equations 'Differential equations of applied mathematics' -- subject(s): Differential equations, Differential equations, Partial, Mathematical physics, Partial Differential equations
Elemer E. Rosinger has written: 'Generalized solutions of nonlinear partial differential equations' -- subject(s): Differential equations, Nonlinear, Differential equations, Partial, Nonlinear Differential equations, Numerical solutions, Partial Differential equations 'Distributions and nonlinear partial differential equations' -- subject(s): Differential equations, Partial, Partial Differential equations, Theory of distributions (Functional analysis)
Victor L. Shapiro has written: 'Fourier series in several variables with applications to partial differential equations' -- subject(s): Partial Differential equations, Functions of several real variables, Fourier series
Richard Haberman has written: 'Applied Partial Differential Equations' 'Elementary applied partial differential equations' -- subject(s): Boundary value problems, Differential equations, Partial, Fourier series, Partial Differential equations
Tian Ma has written: 'Geometric theory of incompressible flows with applications to fluid dynamics' -- subject(s): Differential equations, Partial, Fluid dynamics, Geophysics, Global analysis (Mathematics), Manifolds (Mathematics), Partial Differential equations, Vector fields
Robert Carmichael has written: 'On the general theory of the integration of non-linear partial differential equations' -- subject(s): Differential equations, Partial, Partial Differential equations
Enzo Mitidieri has written: 'Apriori estimates and blow-up of solutions to nonlinear partial differential equations and inequalities' -- subject(s): Differential equations, Nonlinear, Differential equations, Partial, Inequalities (Mathematics), Nonlinear Differential equations, Partial Differential equations