sumti-6 <- ... / lerfu-string !MOI# BOI#? / (LAhE# / NAhE# BO#) relative-clauses? sumti LUhU#? /...
tanru-unit-2 <- ... / ME# (sumti / lerfu-string) MEhU#? MOI#? / (number / lerfu-string) MOI# / NUhA# mex-operator / ...
interval-property <- number ROI# NAI#? / ...
free <- ... / (number / lerfu-string) MAI# / XI# (number BOI# / lerfu-string BOI# / VEI# mex VEhO#?)
quantifier <- number !MOI# BOI#? / VEI# mex VEhO#?
mex <- mex-1 (operator mex-1)* / FUhA# rp-expression
mex-1 <- mex-2 (BIhE# operator mex-1)?
mex-2 <- operand / PEhO#? operator mex-2+ KUhE#?
rp-expression <- operand (rp-expression operator)*
operator <- operator-1 (joik-jek operator-1 / joik stag? KE# operator KEhE#?)*
operator-1 <- operator-2 / guhek operator-1 gik operator-2 / operator-2 (jek / joik) stag? BO# operator-1
operator-2 <- mex-operator / KE# operator KEhE#?
mex-operator <- SE# mex-operator / NAhE# mex-operator / MAhO# mex TEhU#? / NAhU# selbri TEhU#? / VUhU#
operand <- operand-1 (joik-ek stag? KE# operand KEhE#?)?
operand-1 <- operand-2 (joik-ek operand-2)*
operand-2 <- operand-3 (joik-ek stag? BO# operand-2)?
operand-3 <- quantifier / lerfu-string !MOI# BOI#? / NIhE# selbri TEhU#? / MOhE# sumti TEhU#? / JOhI# mex-2+ TEhU#? / gek operand gik operand-3 / (LAhE# / NAhE# BO#) operand LUhU#?
joik <- SE#? JOI# NAI#? / interval / GAhO# interval GAhO#
sumti-6 <- ... / !tag !selbri lerfu-string BOI#? / !tag !selbri (LAhE# / NAhE# BO#) relative-clauses? sumti LUhU#? / ...
tanru-unit-2 <- ... / ME# (sumti / mex) MEhU#? MOI#? / mex MOI# / NUhA# operator / ...
interval-property <- mex ROI# NAI#? / ...
free <- ... / mex-2 MAI# / XI# mex-2
quantifier <- !selbri !sumti-6 mex
mex <- mex-1 (operator mex-1)*
mex-1 <- mex-2 (operator stag? BO# mex-1)?
mex-2 <- number BOI#? / lerfu-string BOI#? / VEI# mex VEhO#? / NIhE# selbri TEhU#? / MOhE# sumti TEhU#? / gek mex gik mex-2 / (LAhE# / NAhE# BO#) mex LUhU#? / PEhO# operator mex+ KUhE#? / FUhA# rp-expression
rp-expression <- mex (rp-expression operator)*
operator <- SE# operator / NAhE# operator / MAhO# mex TEhU#? / NAhU# selbri TEhU#? / VUhU# / JOhI# / joik-jek
It makes sense to unify conjunctions with operators because conjunctions are binary operators. Everything else basicaly follows from that.
There is more freedom for "quantifier", "mex MOI", "mex ROI", "mex-2 MAI" and "XI mex-2".