Shopping cart line quantities SHALL be greater than ZERO.
cac:CatalogueLine/cac:RequiredItemLocationQuantity
(number(cac:Price/cbc:BaseQuantity) > 0) and (number(cac:DeliveryUnit/cbc:BatchQuantity) > 0) or (not(cac:Price/cbc:BaseQuantity)) or (not(cac:DeliveryUnit/cbc:BatchQuantity))