2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/76551In the framework of deformation quantization we define formal KMS states on the deformed algebra of power series of functions with compact support in phase space as C[[λ]]-linear functionals obeying a formal variant of the usual KMS condition known in the theory of C^*-algebras. We show that for each temperature KMS states always exist and are up to a normalization equal to the trace of the argument multiplied by a formal analogue of the usual Boltzmann factor, a certain formal star exponential.11 pages, LaTeX2eQuantum AlgebraSymplectic Geometrytext