| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isnlm.v |  |-  V = ( Base ` W ) | 
						
							| 2 |  | isnlm.n |  |-  N = ( norm ` W ) | 
						
							| 3 |  | isnlm.s |  |-  .x. = ( .s ` W ) | 
						
							| 4 |  | isnlm.f |  |-  F = ( Scalar ` W ) | 
						
							| 5 |  | isnlm.k |  |-  K = ( Base ` F ) | 
						
							| 6 |  | isnlm.a |  |-  A = ( norm ` F ) | 
						
							| 7 | 1 2 3 4 5 6 | isnlm |  |-  ( W e. NrmMod <-> ( ( W e. NrmGrp /\ W e. LMod /\ F e. NrmRing ) /\ A. x e. K A. y e. V ( N ` ( x .x. y ) ) = ( ( A ` x ) x. ( N ` y ) ) ) ) | 
						
							| 8 | 7 | simprbi |  |-  ( W e. NrmMod -> A. x e. K A. y e. V ( N ` ( x .x. y ) ) = ( ( A ` x ) x. ( N ` y ) ) ) | 
						
							| 9 |  | fvoveq1 |  |-  ( x = X -> ( N ` ( x .x. y ) ) = ( N ` ( X .x. y ) ) ) | 
						
							| 10 |  | fveq2 |  |-  ( x = X -> ( A ` x ) = ( A ` X ) ) | 
						
							| 11 | 10 | oveq1d |  |-  ( x = X -> ( ( A ` x ) x. ( N ` y ) ) = ( ( A ` X ) x. ( N ` y ) ) ) | 
						
							| 12 | 9 11 | eqeq12d |  |-  ( x = X -> ( ( N ` ( x .x. y ) ) = ( ( A ` x ) x. ( N ` y ) ) <-> ( N ` ( X .x. y ) ) = ( ( A ` X ) x. ( N ` y ) ) ) ) | 
						
							| 13 |  | oveq2 |  |-  ( y = Y -> ( X .x. y ) = ( X .x. Y ) ) | 
						
							| 14 | 13 | fveq2d |  |-  ( y = Y -> ( N ` ( X .x. y ) ) = ( N ` ( X .x. Y ) ) ) | 
						
							| 15 |  | fveq2 |  |-  ( y = Y -> ( N ` y ) = ( N ` Y ) ) | 
						
							| 16 | 15 | oveq2d |  |-  ( y = Y -> ( ( A ` X ) x. ( N ` y ) ) = ( ( A ` X ) x. ( N ` Y ) ) ) | 
						
							| 17 | 14 16 | eqeq12d |  |-  ( y = Y -> ( ( N ` ( X .x. y ) ) = ( ( A ` X ) x. ( N ` y ) ) <-> ( N ` ( X .x. Y ) ) = ( ( A ` X ) x. ( N ` Y ) ) ) ) | 
						
							| 18 | 12 17 | rspc2v |  |-  ( ( X e. K /\ Y e. V ) -> ( A. x e. K A. y e. V ( N ` ( x .x. y ) ) = ( ( A ` x ) x. ( N ` y ) ) -> ( N ` ( X .x. Y ) ) = ( ( A ` X ) x. ( N ` Y ) ) ) ) | 
						
							| 19 | 8 18 | syl5com |  |-  ( W e. NrmMod -> ( ( X e. K /\ Y e. V ) -> ( N ` ( X .x. Y ) ) = ( ( A ` X ) x. ( N ` Y ) ) ) ) | 
						
							| 20 | 19 | 3impib |  |-  ( ( W e. NrmMod /\ X e. K /\ Y e. V ) -> ( N ` ( X .x. Y ) ) = ( ( A ` X ) x. ( N ` Y ) ) ) |