<div dir="ltr"><div dir="ltr"><div style="font-family:inherit;background-color:transparent;background-image:inherit;background-position:inherit;background-size:inherit;background-repeat:inherit;background-origin:inherit;background-clip:inherit;border-right:inherit;font-size:1.375rem;line-height:28px;margin:0px;padding:0px"><span style="background-color:transparent;font-size:small">Dear Colleagues!</span></div><div style="font-family:inherit;background-color:transparent;background-image:inherit;background-position:inherit;background-size:inherit;background-repeat:inherit;background-origin:inherit;background-clip:inherit;border-right:inherit;font-size:1.375rem;line-height:28px;margin:0px;padding:0px"><span style="background-color:transparent;font-size:small;font-family:inherit">You are cordially invited to the  Weekly Online Seminar “Analysis and Applied Mathematics” on  </span><span style="background-color:transparent;font-family:inherit;font-size:1.375rem">   </span></div><div style="font-family:inherit;background-color:transparent;background-image:inherit;background-position:inherit;background-size:inherit;background-repeat:inherit;background-origin:inherit;background-clip:inherit;border-right:inherit;font-size:1.375rem;line-height:28px;margin:0px;padding:0px"><b style="font-size:small">Date</b><span style="font-size:small">: Tuesday, April 9, 2024 </span></div></div><div dir="ltr"><b>Time:</b> 14.00-15.00 (Istanbul) = 13.00-14.00 (Ghent) = 16.00-17.00 (Almaty)<br>  Place: Zoom link: <a href="https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09" target="_blank">https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09</a>, Conference ID: 667 827 0445, Access code: 1   </div><div dir="ltr"><b>Speaker: </b>  Assoc.Prof. Dr. Fatih Ecevit </div><div dir="ltr"><i>Boğaziçi University, Istanbul, Türkiye </i></div><div dir="ltr"><b>Title: </b>

Computing the infinite tail in the Neumann series representation of high-frequency multiple scattering problems

</div><div dir="ltr"><b>Abstract:</b> We consider the high-frequency multiple scattering problem in the exterior of
several convex obstacles. In this context, we review (1) the single scattering Galerkin boundary element methods (BEM) for the frequency independent approximation of the solutions,
and (2) the Neumann series reformulation of multiple scattering problems along with the
extension of single scattering Galerkin BEM to this case.
These strategies provide the guidelines for the frequency independent approximation of
multiple scattering iterations. However, important additional issues arise in connection with
the Neumann series as it may converge quite slowly or even diverge depending on the underlying geometrical configuration. In this connection, we present our ongoing work on Ray stabilized Galerkin BEM which still uses the Neumann series reformulation even if it may
diverge. Specifically, our approach is based on the calculation of a sufficiently large (depending on the geometry) partial sum of the Neumann series, and computation of the remaining
infinite tail in just one solution through the construction of Ray-stabilized Galerkin BEM.
Time permitting, we also present ongoing work on its Bayliss-Turkel type approximation of
the high-frequency scattering amplitude based on the method of stationary phase, and discuss the extension of this approach to multiple scattering scenarios in conjunction with the
Ray-stabilized Galerkin BEM.</div><div dir="ltr"> <b>Abstracts and forthcoming talks can be found on our webpage</b></div><div dir="ltr"><div><div><div><div><div><a href="https://sites.google.com/view/aam-seminars" rel="noreferrer" target="_blank">https://sites.google.com/view/aam-seminars</a><br>With my best wishes</div></div></div></div></div></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div style="font-size:12.8px"><b style="font-size:12.8px">Prof. Dr. Allaberen Ashyralyev </b></div><div><span style="font-size:small"><b>Department of Mathematics, Bahcesehir University,</b></span><b>34349</b><span style="font-size:small"><b>, Istanbul, Turkiye</b></span><b style="font-size:12.8px">  </b></div><div><div style="font-size:12.8px"><span style="font-size:12.8px"><b>Peoples' Friendship University of Russia (RUDN University),</b></span><b style="color:rgb(51,51,51);font-family:arial,helvetica,sans-serif;font-size:13px"> Ul Miklukho Maklaya 6, Moscow 117198, Russian Federation </b></div><div style="font-size:12.8px"><b style="font-size:12.8px">Institute of Mathematics and Mathematical Modelling, 050010, Almaty, Kazakhstan</b></div><div style="font-size:12.8px"><b style="font-size:12.8px">e-mail: <a href="mailto:allaberen.ashyralyev@neu.edu.tr" style="color:rgb(17,85,204)" target="_blank">allaberen.ashyralyev@bau.edu.tr</a> and </b><b style="font-size:12.8px"><a href="mailto:aallaberen@gmail.com" style="color:rgb(17,85,204)" target="_blank">aallaberen@gmail.com</a> </b></div><div style="font-size:12.8px"><b style="font-size:12.8px"> </b><a href="http://akademik.bahcesehir.edu.tr/web/allaberenashyralyev" style="color:rgb(0,86,179);margin:0px;padding:0px;border:0px;font-stretch:inherit;font-size:14px;line-height:inherit;font-family:Roboto,sans-serif;vertical-align:baseline" target="_blank">http://akademik.bahcesehir.edu.tr/web/allaberenashyralyev</a></div><div><p class="MsoNormal"><a href="https://sites.google.com/view/aam-seminars" target="_blank">https://sites.google.com/view/aam-seminars</a></p><p class="MsoNormal"><a href="https://ejaam.org/editorial.html" target="_blank">https://ejaam.org/editorial.html</a><br></p><p class="MsoNormal"><b style="font-size:12.8px;color:rgb(17,85,204)"><u><a href="http://icaam-online.org" target="_blank">icaam-online.org</a></u></b></p></div></div><div><font color="#1155cc"><span style="font-size:12.8px"><b><a href="https://www.genealogy.math.ndsu.nodak.edu/id.php?id=95872&fChrono=1" target="_blank">https://www.genealogy.math.ndsu.nodak.edu/id.php?id=95872&fChrono=1<br></a></b></span><br></font></div></div></div></div></div></div></div></div></div></div></div></div></div></div>