Theorem s1s7

Description: Concatenation of fixed length strings. (Contributed by Mario Carneiro, 26-Feb-2016)

	Ref	Expression
Assertion	s1s7	|- <" A B C D E F G H "> = ( <" A "> ++ <" B C D E F G H "> )

Proof

Step	Hyp	Ref	Expression
1		df-s7	|- <" B C D E F G H "> = ( <" B C D E F G "> ++ <" H "> )
2		s1cli	|- <" A "> e. Word _V
3		s6cli	|- <" B C D E F G "> e. Word _V
4		df-s8	|- <" A B C D E F G H "> = ( <" A B C D E F G "> ++ <" H "> )
5		s1s6	|- <" A B C D E F G "> = ( <" A "> ++ <" B C D E F G "> )
6	1 2 3 4 5	cats1cat	|- <" A B C D E F G H "> = ( <" A "> ++ <" B C D E F G H "> )