Özkan, MustafaErken, Irem Küpelı2026-02-082026-02-0820251303-59912618-6470https://doi.org/10.31801/cfsuasmas.1485231https://hdl.handle.net/20.500.12885/4961The aim of this paper is to study of the non-trivial solutions of Fischer-Marsden conjecture on K-paracontact manifolds and 3-dimensional quasi-para-Sasakian manifolds. We prove that if a semi-Riemannian manifold of dimension $2n+1$ admits a non-trivial solution of Fischer-Marsden equation, then it has constant scalar curvature. We give a comprehensive classification for a $(2n+1)$-dimensional K-paracontact manifold which admits a non-trivial solution of Fischer-Marsden equation. We consider 3-dimensional quasi-para-Sasakian manifolds with $\\beta$ constant which admits Fischer-Marsden equation and prove that there are two possibilities. The first one is the scalar curvature $r = ?6\\beta^2$ and $M^3$ is Einstein. The second one is the manifold is paracosymplectic manifold and ?-Einstein.eninfo:eu-repo/semantics/openAccessGradient Ricci solitonquasi-para-Sasakian manifoldFischer-Marsden equationK-paracontact manifoldArticle10.31801/cfsuasmas.148523174168781303411