There are m variable in a grammar. The number of productions after removal of unit productions in the worst case is ,(Assume there are no null productions)
He asked about number of total production remains in the minimized grammar , so , if the there is no null production , it is advantage , as you know when we convert a grammar without null production , generally , removal of all production introduces new production in the resultant grammar (it can be upto set of all subset of given max RHS number of variable , so exponetial ) .
But , in given grammar , you don't have null production , so you are removing only unit production (i.e. A--->B type productions ) , resultant grammar maximum 'm' production , where m is number of variable . example :- S---->A A---->B B---->a/b/c resultant grammar , S---->a/b/c So , it is O(m) time .
Can you explain in formal way, please?