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(* as published by the Free Software Foundation; either version 2.1   *)
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(* GNU General Public License for more details.                       *)
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(* 02110-1301 USA                                                     *)

Theorem switch_subs_name :
forall (n n1 n2 : name) (p : PP) (x : VV),
pname p <> n1 ->
vname x <> n2 ->
subs_var_name (subs_par_name n n2 p) n1 x =
subs_par_name (subs_var_name n n1 x) n2 p.