2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/186238We analyze renormalization and the high temperature expansion of the one-loop effective action of the space-time noncommutative ϕ^4 theory by using the zeta function regularization in the imaginary time formalism (i.e., on S^1 x R^3). Interestingly enough, there are no mixed (non-planar) contributions to the counterterms as well as to the power-law high temperature asymptotics. We also study the Wick rotation and formulate assumptions under which the real and imaginary time formalisms are equivalent.24 pages, v2: minor changesHigh Energy Physics - Theorytext