Metamath Proof Explorer

Definition df-s4

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

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

Detailed syntax breakdown

Step Hyp Ref Expression
0 cA 
 |-  A
1 cB 
 |-  B
2 cC 
 |-  C
3 cD 
 |-  D
4 0 1 2 3 cs4 
 |-  <" A B C D ">
5 0 1 2 cs3 
 |-  <" A B C ">
6 cconcat 
 |-  ++
7 3 cs1 
 |-  <" D ">
8 5 7 6 co 
 |-  ( <" A B C "> ++ <" D "> )
9 4 8 wceq 
 |-  <" A B C D "> = ( <" A B C "> ++ <" D "> )