I'm a greenhorn in programming and modelling and I hope somebody could
help me!

I have the following problem with xPress Mosel IVE:

I have a linear program with the following side condition: (Transport
condition)

y1l >= LB1 or y1l = 0

l ... stands for distribution center or consumer
j ... stands for factory 1 or 2
t ... stands for Week 1 to 4

y1l ... Products which are transported from factory 1 to the
distribution center or to the consumer

LB1...The required amount on products which should be transported from
factory 1 to the distribution center or to the consumer

I have input the side condition (Transport condition) in xPress Mosel
IVE as the following but there is always the error message that
something is wrong with the operator or:

forall(l in indexl, j in indexj, t in indext) do
y1l(l, j, t) >= LB1(l, j) or y1l(l, j, t) = 0
end-do

I think that I must input the or condition in another way but I didn't
know how!?

I'm very happy and thankful if somebody could help me,
best regards,