Theorem s6len

Description: The length of a length 6 string. (Contributed by Mario Carneiro, 26-Feb-2016)

	Ref	Expression
Assertion	s6len	$$⊢\left|⟨“ABCDEF”⟩\right|=6$$

Proof

Step	Hyp	Ref	Expression
1		df-s6	$$⊢⟨“ABCDEF”⟩=⟨“ABCDE”⟩\mathrm{++}⟨“F”⟩$$
2		s5cli	$$⊢⟨“ABCDE”⟩\in \mathrm{Word}\mathrm{V}$$
3		s5len	$$⊢\left|⟨“ABCDE”⟩\right|=5$$
4		5p1e6	$$⊢5+1=6$$
5	1 2 3 4	cats1len	$$⊢\left|⟨“ABCDEF”⟩\right|=6$$