[Author]
 Apushkinskaya, D. E.; Nazarov, A. I.

[Title]
 Around the Normal Derivative Lemma

[AMS Subj-class]
 35B50 Maximum principles in context of PDEs
 35J15 Second-order elliptic equations
 35B53 Liouville theorems and Phragmén-Lindelöf theorems in context of PDEs
 35R11 Fractional partial differential equations

[Keywords]
 strong maximum principle, the Hopf--Oleinik lemma, the Harnack inequality, 
 the Aleksandrov--Bakel'man maximum principle

[Abstract]
 This is a survey. It describes the history and present state of one of 
 the most important fields in the qualitative theory of elliptic partial 
 differential equations related to the Strong Maximum Principle and 
 Boundary Point Principle (the normal derivative lemma).
 Bibliography: 359 titles

[Comments]
 LaTeX, Russian, 96 pp.

[Contact e-mail]
 al.il.nazarov@gmail.com