Evolution of the disc mass function (DMF) due to dynamical encounters at an age of 3 Myr for densities { 2.25 × 10⁴,2.5 × 10³,5 × 10² } pc^-2 (solid, dashed, dash-dotted), sampling NGC 3603 at radius intervals of { 0′′ − 5′′,16.5′′ − 43.5′′,46.5′′ − 73.5′′ } . The dotted curve shows the initial DMF, and the vertical dotted line indicates the 4σ sensitivity limit of ALMA Cycle 1 (30 min at 1.3 mm) at the distance of NGC 3603.