1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| A.Asperti, C.Sacerdoti Coen, *)
8 (* ||A|| E.Tassi, S.Zacchiroli *)
10 (* \ / Matita is distributed under the terms of the *)
11 (* v GNU Lesser General Public License Version 2.1 *)
13 (**************************************************************************)
15 set "baseuri" "cic:/matita/nat/sigma_and_pi".
17 include "nat/times.ma".
19 let rec sigma n f \def
22 | (S p) \Rightarrow (f p)+(sigma p f)].
27 | (S p) \Rightarrow (f p)*(pi p f)].