“…The idea is to deduce, from the equations of (5.2) that the norm of modulo constants in L 2 .0, T 1 ; H 1 .l, r// is bounded by the norm of v in L 2 .0, T 1 ; L 2 .l, r//, that is, k k L 2 .0,T1;H 1 .l,r// Ä Ckvk L 2 .0,T1;L 2 .l,r// . (5.6) More precisely, a bounded operator K from L 2 .0, T 1 ; L 2 .l, r// to L 2 .0, T 1 ; H 1 .l, r// is to be constructed in the next subsection (Equation 5.15) such that D Kv. Using this, we set O g D K f .…”