Interchange of the Degrees of Comparison

Positive. -- I am as strong as him.
Comparative. -- He is not stronger than me.
Positive. --This razor is not as sharp as that one.
Comparative. -- That razor is sharper than this one.
Positive. -- Few historians write as interestingly as Joshi.
Comparative. -- Joshi writes more interestingly than most historians.
Positive. -- No other metal is as useful as iron.
Comparative. -- Iron is more useful than any other metal.
Superlative. -- Iron is the most useful of all metals.
Superlative. -- India is the largest democracy in the world.
Comparative. -- India is larger than any other democracy in the world.
Positive. -- No other democracy in the world is as large as India.
Superlative. -- Mumbai is one of the richest cities in India.
Comparative. -- Mumbai is richer than most other cities in India.
Positive. -- Very few cities in India are as rich as Mumbai.
Superlative. -- Usha Kiran is not the tallest of all the buildings in the city.
Comparative. -- Usha Kiran is not taller than some other buildings in the city.
OR
Some other buildings in the city are perhaps tatter than Usha Kiran.
positive. -- Some other buildings in the city are at least as tall as Usha Kiran.
OR
Usha Kiran is perhaps not as tall as some other buildings in the city.
Superlative. -- Naomi is not one of the cleverest girls in the class.
Comparative. -- Some girls of the class are cleverer than Naomi,.
OR
Naomi is less clever than some other girls of the class.
Positive. -- Naomi is not so clever as some other girls of the class.