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update in ground
[helm.git] / matita / matita / contribs / lambdadelta / ground / arith / arith_2a.ma
index 92224c4c9560d1f51b5c54e52c144fda38b2ec00..a136174bc8b209fc0c813c013b3382cdca587938 100644 (file)
 (*                                                                        *)
 (**************************************************************************)
 
-include "ground/notation/functions/two_0.ma".
+include "ground/arith/pnat_two.ma".
 include "ground/arith/nat_le_minus_plus.ma".
 include "ground/arith/nat_lt.ma".
 
 (* ARITHMETICAL PROPERTIES FOR λδ-2A ****************************************)
 
-interpretation
-  "zero (non-negative integers)"
-  'Two = (ninj (psucc punit)).
-
 (* Equalities ***************************************************************)
 
 lemma plus_n_2: ∀n. (n + 𝟐) = n + 𝟏 + 𝟏.