M I Belishev and N Wada 2009 Inverse Problems 25 105011 doi:10.1088/0266-5611/25/10/105011
M I Belishev1 and N Wada2
Show affiliationsThis paper deals with boundary value inverse problems on a metric graph, the structure of the graph being assumed unknown. The question under consideration is how to detect from the dynamical and/or spectral inverse data whether the graph contains cycles (is not a tree). For any graph Ω, the dynamical as well as spectral boundary inverse data determine the so-called wave diameter
defined on functionals supported in the graph. The known fact is that if Ω is a tree then dw ≥ 0 holds and, in this case, the inverse data determine Ω up to isometry. A graph Ω is said to be coordinate if the functions {distΩ(
, γ)}γ
∂Ω constitute a coordinate system on Ω. For such graphs, we propose a procedure, which reveals the presence/absence of cycles. The hypothesis is that Ω contains cycles if and only if dw takes negative values. We do not justify this hypothesis in the general case but reduce it to a certain special class of graphs (suns).
02.60.Lj Ordinary and partial differential equations; boundary value problems
Issue 10 (October 2009)
Received 29 June 2009, in final form 11 August 2009
Published 1 October 2009
M I Belishev and N Wada 2009 Inverse Problems 25 105011
Ronny Richter 2009 Class. Quantum Grav. 26 145017
A Z AlZahrani et al 2009 J. Phys.: Condens. Matter 21 485504
G M Webb and G P Zank 2009 J. Phys. A: Math. Theor. 42 475205
J M Coupland and J Lobera 2008 Meas. Sci. Technol. 19 074012
Jun Xia and Andreas Mandelis 2009 Semicond. Sci. Technol. 24 125002
I González et al 2008 J. Phys.: Condens. Matter 20 264002
H Zhang and K Ravi-Chandar 2009 J. Phys. D: Appl. Phys. 42 214010
G Beutier et al 2009 New J. Phys. 11 113026
O Vilhu et al 1998 Phys. Scr. 1998 27