AU - Abbasi, Naser AU - Moiseev, Evgenii Ivanovich TI - On the Basis Property of an Trigonometric Functions System of The Frankl Problem With a Non-Local Parity Condition of the First Kind in the Sobolev Space `overline(W)_p^(2l) (0,pi)` PT - JOURNAL ARTICLE TA - lu-maco JN - lu-maco VO - 1 VI - 1 IP - 1 4099 - http://maco.lu.ac.ir/article-1-43-en.html 4100 - http://maco.lu.ac.ir/article-1-43-en.pdf SO - lu-maco 1 ABĀ  - In the present paper, we write out the eigenvalues and the corresponding eigenfunctions of the modified Frankl problem with a nonlocal parity condition of the first kind. We analyze the completeness, the basis property, and the minimality of the eigenfunctions in the space `overline(W)_p^(2l) (0,pi)`, where `overline(W)_p^(2l) (0,pi)` be the set of functions `f in W_p^(2l) (0,pi)`, satisfying of the following conditions: `f^{(2k-1)}(0)=0, k=1,2,...,l`. CP - IRAN IN - Department of Mathematics, Lorestan University, P. O. Box 465, Khoramabad, Iran LG - eng PB - lu-maco PG - 41 PT - Research Article YR - 2020