sumdaiklei fu'ivla

x1 (mass) is the object type of argument object x2, as defined by property x3 (ka)

See sumdai, kleinzu. Examples of Lojban sumdaiklei: nundumu, du'umdu, li'imdu, sidbo (= si'omdu), zilkai, su'umdu, nildumu

In notes:

nildumu
x1 (ni) is a quantity
si'omdu
x1 (si'o) is an idea/concept/thought about x2 (object/abstract) by thinker x3.