“…Denote the Gelfand-Shilov space of order 1/2 by S 1/2 , and the weighted modulation space with Lebesgue parameters p, q > 0 and with weight ω by M p,q (ω) . Then the map (a 1 , a 2 ) → a 1 #a 2 from S 1/2 (R 2d ) × S 1/2 (R 2d ) to S 1/2 (R 2d ) extends uniquely to a continuous map from M p 1 ,q 1 (ω 1 ) (R 2d ) × M p 2 ,q 2 (ω 2 ) (R 2d ) to M p 0 ,q 0 (ω 0 ) (R 2d ), and a 1 #a 2 M p 0 ,q 0 (ω 0 )…”