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authorGravatar Maxime Dénès <mail@maximedenes.fr>2017-04-27 21:30:53 +0200
committerGravatar Maxime Dénès <mail@maximedenes.fr>2017-04-27 21:30:53 +0200
commit0a255f51809e8d29a7239bfbd9fe57a8b2b41705 (patch)
tree9f9b9515dc1bdddf17ab8746a7a061d23d6b15ca /theories/Reals/Rpower.v
parentcc12397b32785b06ed892e8ad420cfe253842141 (diff)
parentf5c81ac1bcae7c40d5e89229647c06c97b5ddc85 (diff)
Merge PR#414: Some more theory on powerRZ.
Diffstat (limited to 'theories/Reals/Rpower.v')
-rw-r--r--theories/Reals/Rpower.v14
1 files changed, 14 insertions, 0 deletions
diff --git a/theories/Reals/Rpower.v b/theories/Reals/Rpower.v
index b8040bb4f..0e0246cbf 100644
--- a/theories/Reals/Rpower.v
+++ b/theories/Reals/Rpower.v
@@ -473,6 +473,20 @@ Proof.
apply exp_Ropp.
Qed.
+Lemma powerRZ_Rpower x z : (0 < x)%R -> powerRZ x z = Rpower x (IZR z).
+Proof.
+ intros Hx.
+ assert (x <> 0)%R
+ by now intros Habs; rewrite Habs in Hx; apply (Rlt_irrefl 0).
+ destruct (intP z).
+ - now rewrite Rpower_O.
+ - rewrite <- pow_powerRZ, <- Rpower_pow by assumption.
+ now rewrite INR_IZR_INZ.
+ - rewrite opp_IZR, Rpower_Ropp.
+ rewrite powerRZ_neg, powerRZ_inv by assumption.
+ now rewrite <- pow_powerRZ, <- INR_IZR_INZ, Rpower_pow.
+Qed.
+
Theorem Rle_Rpower :
forall e n m:R, 1 < e -> 0 <= n -> n <= m -> e ^R n <= e ^R m.
Proof.