首楞嚴義疏注經 3.318

3.318

隣虛，無方分微也，即是極微色邊際相。微塵，有方分微也。今經指有方分微名色邊際相，隨經所出，不須和會。

The particle bordering on voidness is a subtle particle without spatial divisions; it is precisely the boundary mark of matter, the paramāṇu. A subtle particle of dust (aṇu) is a subtle particle with spatial divisions. Now the sūtra refers to the particle with spatial divisions as the boundary mark of matter; following what the sūtra sets forth, there is no need to reconcile them.