1.1 --- a/src/HOL/Library/Inner_Product.thy	Thu Jan 31 12:09:07 2013 +0100
     1.2 +++ b/src/HOL/Library/Inner_Product.thy	Thu Jan 31 17:42:12 2013 +0100
     1.3 @@ -117,8 +117,6 @@
     1.4  subclass real_normed_vector
     1.5  proof
     1.6    fix a :: real and x y :: 'a
     1.7 -  show "0 \<le> norm x"
     1.8 -    unfolding norm_eq_sqrt_inner by simp
     1.9    show "norm x = 0 \<longleftrightarrow> x = 0"
    1.10      unfolding norm_eq_sqrt_inner by simp
    1.11    show "norm (x + y) \<le> norm x + norm y"