let V be RealLinearSpace; :: thesis: for u, v, x, y being VECTOR of V holds u,v, Ortm (x,y,u), Ortm (x,y,v) are_COrtm_wrt x,y
let u, v, x, y be VECTOR of V; :: thesis: u,v, Ortm (x,y,u), Ortm (x,y,v) are_COrtm_wrt x,y
Ortm (x,y,u), Ortm (x,y,v) // Ortm (x,y,u), Ortm (x,y,v) by ANALOAF:8;
hence u,v, Ortm (x,y,u), Ortm (x,y,v) are_COrtm_wrt x,y by Def4; :: thesis: verum