| Step | Hyp | Ref | Expression | 
						
							| 1 |  | sqdeccom12.a |  | 
						
							| 2 |  | sqdeccom12.b |  | 
						
							| 3 |  | sq3deccom12.c |  | 
						
							| 4 |  | sq3deccom12.d |  | 
						
							| 5 |  | 0nn0 |  | 
						
							| 6 |  | eqid | Could not format  ; C 0 = ; C 0 : No typesetting found for |- ; C 0 = ; C 0 with typecode |- | 
						
							| 7 |  | eqid | Could not format  ; A B = ; A B : No typesetting found for |- ; A B = ; A B with typecode |- | 
						
							| 8 | 1 | nn0cni |  | 
						
							| 9 | 3 | nn0cni |  | 
						
							| 10 | 8 9 4 | addcomli |  | 
						
							| 11 | 2 | nn0cni |  | 
						
							| 12 | 11 | addlidi |  | 
						
							| 13 | 3 5 1 2 6 7 10 12 | decadd | Could not format  ( ; C 0 + ; A B ) = ; D B : No typesetting found for |- ( ; C 0 + ; A B ) = ; D B with typecode |- | 
						
							| 14 | 1 2 | deccl | Could not format  ; A B e. NN0 : No typesetting found for |- ; A B e. NN0 with typecode |- | 
						
							| 15 | 14 | nn0cni | Could not format  ; A B e. CC : No typesetting found for |- ; A B e. CC with typecode |- | 
						
							| 16 | 15 | addlidi | Could not format  ( 0 + ; A B ) = ; A B : No typesetting found for |- ( 0 + ; A B ) = ; A B with typecode |- | 
						
							| 17 | 3 5 14 6 16 | decaddi | Could not format  ( ; C 0 + ; A B ) = ; C ; A B : No typesetting found for |- ( ; C 0 + ; A B ) = ; C ; A B with typecode |- | 
						
							| 18 | 13 17 | eqtr3i | Could not format  ; D B = ; C ; A B : No typesetting found for |- ; D B = ; C ; A B with typecode |- | 
						
							| 19 | 18 18 | oveq12i | Could not format  ( ; D B x. ; D B ) = ( ; C ; A B x. ; C ; A B ) : No typesetting found for |- ( ; D B x. ; D B ) = ( ; C ; A B x. ; C ; A B ) with typecode |- | 
						
							| 20 | 19 | oveq2i | Could not format  ( ( ; ; A B C x. ; ; A B C ) - ( ; D B x. ; D B ) ) = ( ( ; ; A B C x. ; ; A B C ) - ( ; C ; A B x. ; C ; A B ) ) : No typesetting found for |- ( ( ; ; A B C x. ; ; A B C ) - ( ; D B x. ; D B ) ) = ( ( ; ; A B C x. ; ; A B C ) - ( ; C ; A B x. ; C ; A B ) ) with typecode |- | 
						
							| 21 | 14 3 | sqdeccom12 | Could not format  ( ( ; ; A B C x. ; ; A B C ) - ( ; C ; A B x. ; C ; A B ) ) = ( ; 9 9 x. ( ( ; A B x. ; A B ) - ( C x. C ) ) ) : No typesetting found for |- ( ( ; ; A B C x. ; ; A B C ) - ( ; C ; A B x. ; C ; A B ) ) = ( ; 9 9 x. ( ( ; A B x. ; A B ) - ( C x. C ) ) ) with typecode |- | 
						
							| 22 | 20 21 | eqtri | Could not format  ( ( ; ; A B C x. ; ; A B C ) - ( ; D B x. ; D B ) ) = ( ; 9 9 x. ( ( ; A B x. ; A B ) - ( C x. C ) ) ) : No typesetting found for |- ( ( ; ; A B C x. ; ; A B C ) - ( ; D B x. ; D B ) ) = ( ; 9 9 x. ( ( ; A B x. ; A B ) - ( C x. C ) ) ) with typecode |- |