Question

As by default sequence order is not maintained in an OWL ontology. How can i model sequence in an OWL-DL ontology ?

Answer 1

One way to model a sequence and order its elements is to just introduc a hasNext property to capture sequence order:

Class: SequenceItem
    EquivalentTo: 
        hasNext only SequenceItem

ObjectProperty: hasNext 
    Domain: 
       SequenceItem
    Range: 
       SequenceItem
    InverseOf:
       hasPrevious

Then, assuming the items you want to sequence in order are represented as instances, you can capture their order in the sequence like so:

SequenceItem: item_1
    hasNext: 
         item_2