Understanding Patent Rights

Here you will get a clear picture by reading the following simple example “stool and chair invention concept”, which is familiar to all patent practitioners.
A portable seating appliance art ‘stool’ having platform with three legs was invented by Abraham. And he applied for a patent and obtained patent grant for his invention.
Another inventor Bartholomew had come with invention “chair”, in which he added a fourth leg, back support and arm support to have more comfortable. As the “chair’ has improvement over the ‘stool’, the patent office granted a patent to Bartholomew for his invention.
Now there is interesting question, who owns what rights?
Abraham invented basic portable appliance art ‘stool’, and he can exclude others from making, using, or selling his stool invention and also he can make, use and sell his invention ‘stool’ with out any fear of infringing others patent right. Hence, he has both negative right and positive right on his invention.
Where as, Bartholomew can only exclude [negative right] others from making, using or selling devices which has four leg, back support and arm support, and his patent does not give him any right to make these devices. Indeed, since chair also has a platform and three legs [which is equivalent to stool], if chairs are made without obtaining a license from Abraham, then it will be infringing Abraham’s stool patent.
Thus, it will be clear that a person having a patent does not give that person the right to practice his invention. The basic patent only has both positive and negative right, where as all improvement patent enables their owner to exclude others from practicing their patented products.