%0 Journal Article %T W1,q stability of the Fortin operator for the MAC scheme %+ Laboratoire d'Analyse, Topologie, Probabilités (LATP) %+ Institut de Radioprotection et de Sûreté Nucléaire (IRSN) %A Gallouët, Thierry %A Herbin, Raphaele %A Latché, Jean-Claude %< avec comité de lecture %@ 0008-0624 %J Calcolo %I Springer Verlag %V 49 %N 1 %P 63-71 %8 2012-02-24 %D 2012 %R 10.1007/s10092-011-0045-x %K MAC scheme %K Projection stability %K Fortin operator %Z 65M12, 76D07, 76M12 %Z Mathematics [math]/Numerical Analysis [math.NA]Journal articles %X We prove in this paper the continuity of the natural pro- jection operator from W1,q(Ω)d to the MAC discrete space of piece- 0 wise constant functions over the dual cells, endowed with the finite volume W1,q-discrete norm. Since this projection operator is also a Fortin operator (that is an operator which "preserves" the diver- gence), this result may be applied to control the pressure in mixed problems where the test function for the velocity must be more reg- ular than usual (i.e. more regular than H01(Ω)d). %G English %2 https://hal.science/hal-00673682/document %2 https://hal.science/hal-00673682/file/fortin-mac-10.pdf %L hal-00673682 %U https://hal.science/hal-00673682 %~ IRSN %~ LATP %~ CNRS %~ UNIV-AMU %~ EC-MARSEILLE %~ I2M %~ TDS-MACS