umre fu'ivla

x1 (set) is measurable and has measure x2 (li; non-negative real number or possibly positive infinity) by measure x3 in space/dimensionality/under conditions x4; x2 is the x3 measure of set x1 in space x4; x3 is a measure which is defined on some class of measurable sets in x4 such that it maps x1 to x2

A type of klenilbra (notice rearranged terbri). "Measure-0 set" = "set of measure 0" = "lo umre be li no". 0 is indeed a measure (value). In general, this dictionary definition does not require that there exists at least one measurable set that gets mapped by x3 to a finite (x2) value; that condition may be imposed by context.

In notes:

zi'au (exp!)
nonexistent/undefining it; the selbri is not applicable when the other terbri are filled in the manner in which they are in this utterance/bridi.