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Continuation of solutions of elliptic systems from discrete sets with application to geometry of surfaces

  • Alexander Bukhgeim , Jin Cheng , Cristina C. Domme EMAIL logo and Shuai Lu
Published/Copyright: February 27, 2025

Abstract

We obtain new estimates of stability for the continuation of solutions of elliptic inequalities | ¯ u | 2 a | u | 2 from finite discrete sets. For this, we use Hörmander’s type of Carleman estimates for ¯ with boundary terms and a special weight function equal to the linear combination of Green’s functions with singularities at points where our function is given. To estimate functions in a given domain we use not only the classical Blaschke partial sum S n but we also introduce a new sequence of numbers M n which gives us better estimates in the case of a finite number of observations.

MSC 2020: 35A05; 32W05; 30H20

Appendix

The figures below show the numbers M n and B n as functions of ρ for different values of r and n.

Figure 4 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.1
                              
                           
                           
                           r=0.1
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 5
                              
                           
                           
                           n=5
                        
                     .
Figure 4

Graphing M n and B n for r = 0.1 and n = 5 .

Figure 5 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.1
                              
                           
                           
                           r=0.1
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 10
                              
                           
                           
                           n=10
                        
                     .
Figure 5

Graphing M n and B n for r = 0.1 and n = 10 .

Figure 6 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.1
                              
                           
                           
                           r=0.1
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 50
                              
                           
                           
                           n=50
                        
                     .
Figure 6

Graphing M n and B n for r = 0.1 and n = 50 .

Figure 7 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.1
                              
                           
                           
                           r=0.1
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 100
                              
                           
                           
                           n=100
                        
                     .
Figure 7

Graphing M n and B n for r = 0.1 and n = 100 .

Figure 8 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.5
                              
                           
                           
                           r=0.5
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 5
                              
                           
                           
                           n=5
                        
                     .
Figure 8

Graphing M n and B n for r = 0.5 and n = 5 .

Figure 9 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.5
                              
                           
                           
                           r=0.5
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 10
                              
                           
                           
                           n=10
                        
                     .
Figure 9

Graphing M n and B n for r = 0.5 and n = 10 .

Figure 10 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.5
                              
                           
                           
                           r=0.5
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 50
                              
                           
                           
                           n=50
                        
                     .
Figure 10

Graphing M n and B n for r = 0.5 and n = 50 .

Figure 11 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.5
                              
                           
                           
                           r=0.5
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 100
                              
                           
                           
                           n=100
                        
                     .
Figure 11

Graphing M n and B n for r = 0.5 and n = 100 .

Figure 12 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.9
                              
                           
                           
                           r=0.9
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 5
                              
                           
                           
                           n=5
                        
                     .
Figure 12

Graphing M n and B n for r = 0.9 and n = 5 .

Figure 13 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.9
                              
                           
                           
                           r=0.9
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 10
                              
                           
                           
                           n=10
                        
                     .
Figure 13

Graphing M n and B n for r = 0.9 and n = 10 .

Figure 14 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.9
                              
                           
                           
                           r=0.9
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 50
                              
                           
                           
                           n=50
                        
                     .
Figure 14

Graphing M n and B n for r = 0.9 and n = 50 .

Figure 15 
                  Graphing 
                        
                           
                              
                                 M
                                 n
                              
                           
                           
                           M_{n}
                        
                      and 
                        
                           
                              
                                 B
                                 n
                              
                           
                           
                           B_{n}
                        
                      for 
                        
                           
                              
                                 r
                                 =
                                 0.9
                              
                           
                           
                           r=0.9
                        
                      and 
                        
                           
                              
                                 n
                                 =
                                 100
                              
                           
                           
                           n=100
                        
                     .
Figure 15

Graphing M n and B n for r = 0.9 and n = 100 .

References

[1] A. L. Bukhgeĭm, Extension of solutions of elliptic equations from discrete sets, J. Inverse Ill-Posed Probl. 1 (1993), no. 1, 17–32. 10.1515/jiip.1993.1.1.17Search in Google Scholar

[2] T. Carleman, Sur un problème d’unicité pur les systèmes d’équations aux dérivées partielles à deux variables indépendantes, Ark. Mat. Astr. Fys. 26 (1939), no. 17, 9. Search in Google Scholar

[3] J. B. Garnett, Bounded Analytic Functions, Pure Appl. Math. 96, Academic Press, New York, 1981. Search in Google Scholar

[4] L. Hörmander, An Introduction to Complex Analysis in Several Variables, D. Van Nostrand, Princeton, 1966. Search in Google Scholar

[5] M. M. Lavrent’ev, Some Improperly Posed Problems of Mathematical Physics, Springer Tracts Natural Philos. 11, Springer, Berlin, 1967. 10.1007/978-3-642-88210-4Search in Google Scholar

[6] S. P. Shishat’skiĭ, Interior problems for elliptic and parabolic equations, and Carleman estimates with distributed singularities, Sov. Math Dokl. 36 (1988), no. 3, 516–518. Search in Google Scholar

Received: 2025-01-27
Accepted: 2025-01-29
Published Online: 2025-02-27
Published in Print: 2025-06-01

© 2025 Walter de Gruyter GmbH, Berlin/Boston

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