2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/173887Let $G={\rm Spec} A$ be a linearly reductive group and let $w_G\in A^*$ be the invariant integral on $G$. We establish the harmonic analysis on $G$ and we compute $w_G$ when $G=Sl_n, Gl_n, O_n, Sp_{2n}$ by geometric arguments and by means of the Fourier transform.17 pages, some new results addedAlgebraic GeometryCommutative Algebra14L24 (Primary) 14L17 (Secondary)Invariant integral on classical groups and algebraic harmonic analysistext