Theorem helloworld

Description: The classic "Hello world" benchmark has been translated into 314 computer programming languages - see http://helloworldcollection.de . However, for many years it eluded a proof that it is more than just a conjecture, even though a wily mathematician once claimed, "I have discovered a truly marvelous proof of this, which this margin is too narrow to contain." Using an IBM 709 mainframe, a team of mathematicians led by Prof. Loof Lirpa, at the New College of Tahiti, were finally able put it rest with a remarkably short proof only 4 lines long. (Contributed by Prof. Loof Lirpa, 1-Apr-2007) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	helloworld	|- -. ( h e. ( L L 0 ) /\ W (/) ( R. 1 d ) )

Proof

Step	Hyp	Ref	Expression
1		noel	|- -. <. W , ( R. 1 d ) >. e. (/)
2		df-br	|- ( W (/) ( R. 1 d ) <-> <. W , ( R. 1 d ) >. e. (/) )
3	1 2	mtbir	|- -. W (/) ( R. 1 d )
4	3	intnan	|- -. ( h e. ( L L 0 ) /\ W (/) ( R. 1 d ) )