diff -r c8a474a919a7 -r 2d91b2416de8 src/HOL/Library/Inner_Product.thy
--- a/src/HOL/Library/Inner_Product.thy	Thu Jun 04 14:32:00 2009 -0700
+++ b/src/HOL/Library/Inner_Product.thy	Thu Jun 04 16:11:36 2009 -0700
@@ -10,6 +10,14 @@
 
 subsection {* Real inner product spaces *}
 
+text {* Temporarily relax constraints for @{term dist} and @{term norm}. *}
+
+setup {* Sign.add_const_constraint
+  (@{const_name dist}, SOME @{typ "'a::dist \<Rightarrow> 'a \<Rightarrow> real"}) *}
+
+setup {* Sign.add_const_constraint
+  (@{const_name norm}, SOME @{typ "'a::norm \<Rightarrow> real"}) *}
+
 class real_inner = real_vector + sgn_div_norm + dist_norm + topo_dist +
   fixes inner :: "'a \<Rightarrow> 'a \<Rightarrow> real"
   assumes inner_commute: "inner x y = inner y x"
@@ -116,6 +124,14 @@
 
 end
 
+text {* Re-enable constraints for @{term dist} and @{term norm}. *}
+
+setup {* Sign.add_const_constraint
+  (@{const_name dist}, SOME @{typ "'a::metric_space \<Rightarrow> 'a \<Rightarrow> real"}) *}
+
+setup {* Sign.add_const_constraint
+  (@{const_name norm}, SOME @{typ "'a::real_normed_vector \<Rightarrow> real"}) *}
+
 interpretation inner:
   bounded_bilinear "inner::'a::real_inner \<Rightarrow> 'a \<Rightarrow> real"
 proof