2D angular completeness function of galaxy-galaxy pairs (see Eq. (15)) observed in 2170 survey realisations with respect to the VIPERS parent catalogue. Left panel: survey realisations are obtained spatially moving the spectroscopic mask over the parent catalogue. The rectangular “shadow” at small separations is the typical footprint of VIMOS spectra. Right panel: as in the left panel but when also the rotations of the parent catalogue are added to make multiple survey realisations. The size of the square shadow at small pair separations in the right panel is the typical length of VIMOS slits and is produced by the slit collisions only.