(a) Present a predicate calculus formalization for the Confusion–of-Patents Problem (Exercise 3–3) and give a resolution-based proof that it is solvable.

(b) Use the technique of example construction to find the solution to the problem.

Exercise 3–3

A certain patent attorney was astonished when he received the simultaneous allowance of five patents, for five separate clients, each of whom lived in a different city.

His astonishment turned to chagrin, however, when he learned what had happened to the patents. They had been received in his office on the same day, but because of an error made by a new clerk, they were sent out in wrong envelopes. Each client received a patent, but not his own.

The inventor of the steam shovel received the mousetrap patent, while the inventor of the latter found in his mail the papers that should have gone to Mr. Green. Mr. Blue received the patent for the rumbleseat awning. Mr. Black's patent was sent to Chicago; the patent that should have gone was sent to Boston.

Mr. Brown had the patent intended for New York. Mr White had Mr. Brown's patent. The nonrefillable bottle patent was sent to Los Angeles; the inventor of the bottle received the patent of the Cleveland client, while in Cleveland the surprised client received a patent for an antisnore device.

Who should have received what where?