Columbia subject headings:
Differential equations, Elliptic.
Differential equations, Parabolic.
Variational inequalities (Mathematics)
Harvard subject headings:
Differential equations, Elliptic.
Differential equations, Parabolic.
Variational inequalities (Mathematics)
Princeton subject headings:
Differential equations, Elliptic.
Differential equations, Parabolic.
Variational inequalities (Mathematics)