diff options
Diffstat (limited to 'Common/Nat.lean')
| -rw-r--r-- | Common/Nat.lean | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Common/Nat.lean b/Common/Nat.lean index 9d0ee29..bc66a09 100644 --- a/Common/Nat.lean +++ b/Common/Nat.lean @@ -23,3 +23,6 @@ theorem lt_of_pred_lt {a b : Nat} (h₁ : a < b.pred) : (a < b) := theorem lt_imp_pred_lt {a b : Nat} (h₁ : a < b) : (a.pred < b) := Nat.lt_of_le_of_lt (Nat.pred_le a) h₁ + +theorem le_of_add_le {a b c d : Nat} (h₁ : a ≤ b + c) (h₂ : c ≤ d) : a ≤ b + d := + Nat.le_trans h₁ (Nat.add_le_add_left h₂ b) |