Definition df-s4 11552

Description: Define the length 4 word constructor. (Contributed by Mario Carneiro, 26-Feb-2016.)

Assertion

Ref	Expression
df-s4	|- <" A B C D "> = ( <" A B C "> ++ <" D "> )

Detailed syntax breakdown of Definition df-s4

Step	Hyp	Ref	Expression
1		cA	. . 3 class A
2		cB	. . 3 class B
3		cC	. . 3 class C
4		cD	. . 3 class D
5	1, 2, 3, 4	cs4 11545	. 2 class <" A B C D ">
6	1, 2, 3	cs3 11544	. . 3 class <" A B C ">
7	4	cs1 11405	. . 3 class <" D ">
8		cconcat 11380	. . 3 class ++
9	6, 7, 8	co 6088	. 2 class ( <" A B C "> ++ <" D "> )
10	5, 9	wceq 1402	1 wff <" A B C D "> = ( <" A B C "> ++ <" D "> )

This definition is used by:  s4eqd  11566  s4cld  11574  s1s3d  11589  s1s4d  11590  s2s2d  11594  s4s4d  11600  konigsberglem1  16934  konigsberglem2  16935  konigsberglem3  16936