costing query- transportation


 i have a query  from the transportation chapter of cost management. while solving a transportation problem, suppose we have the initial basic feasible solution. but there is degeneracy so we need to allocate 'e' to least cost independent cell. so my question is, what do we mean by 'independent cell'? i came across this transportation question from may 07 and the solution stated that the least cost cell was not 'independent cell' therefore 'e' was allocated to the next least cost and independent cell. anyone?