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 to put it to rest with a remarkably short proof only four lines long. (Contributed by Prof. Loof Lirpa, 1-Apr-2007) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	helloworld	$$⊢\neg \left(h\in \left(LL0\right)\wedge W\varnothing \left(𝑹1d\right)\right)$$

Proof

Step	Hyp	Ref	Expression
1		noel	$$⊢\neg ⟨W,𝑹1d⟩\in \varnothing$$
2		df-br	$$⊢W\varnothing \left(𝑹1d\right)\leftrightarrow ⟨W,𝑹1d⟩\in \varnothing$$
3	1 2	mtbir	$$⊢\neg W\varnothing \left(𝑹1d\right)$$
4	3	intnan	$$⊢\neg \left(h\in \left(LL0\right)\wedge W\varnothing \left(𝑹1d\right)\right)$$