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-rw-r--r--consecutive-fibonacci-numbers-are-coprime.lisp5
1 files changed, 4 insertions, 1 deletions
diff --git a/consecutive-fibonacci-numbers-are-coprime.lisp b/consecutive-fibonacci-numbers-are-coprime.lisp
index d80ce43..482eb65 100644
--- a/consecutive-fibonacci-numbers-are-coprime.lisp
+++ b/consecutive-fibonacci-numbers-are-coprime.lisp
@@ -5,6 +5,7 @@
;; フィボナッチ関数の定義
(defun fibonacci (n)
+ (declare (xargs :guard (natp n)))
(cond
((zp n) 0)
((equal n 1) 1)
@@ -13,7 +14,9 @@
;; ユークリッドの互除法による最大公約数の定義
(defun gcd$ (n m)
- (declare (xargs :measure (+ (nfix m) (nfix n))))
+ (declare (xargs :measure (+ (nfix m) (nfix n))
+ :guard (and (posp n)
+ (posp m))))
(cond
((or (not (posp n))
(not (posp m))