diff --git a/theories/xmathcomp/algR.v b/theories/xmathcomp/algR.v
index 0f02339..38e7d59 100644
--- a/theories/xmathcomp/algR.v
+++ b/theories/xmathcomp/algR.v
@@ -1,5 +1,5 @@
 From HB Require Import structures.
-From mathcomp Require Import all_ssreflect all_fingroup all_algebra.
+From mathcomp Require Import all_ssreflect all_fingroup all_algebra archimedean.
 From mathcomp Require Import all_solvable all_field.
 From Abel Require Import various.
 
@@ -65,14 +65,14 @@ End Num.
 
 Definition algR_archiFieldMixin : Num.archimedean_axiom algR.
 Proof.
-move=> /= x; have /andP[/= _] := floorC_itv (valP `|x|).
-set n := floorC _; have [n_lt0|n_ge0] := ltP n 0.
+move=> /= x; have /andP[/= _] := real_floor_itv (valP `|x|).
+set n := Num.floor _; have [n_lt0|n_ge0] := ltP n 0.
   move=> /(@lt_le_trans _ _ _ _ 0); rewrite lerz0 lezD1.
   by move=> /(_ n_lt0); rewrite normr_lt0.
 move=> x_lt; exists (`|(n + 1)%R|%N); apply: lt_le_trans x_lt _.
 by rewrite /= rmorphMn/= pmulrn gez0_abs// addr_ge0.
 Qed.
-HB.instance Definition _ := Num.RealField_isArchimedean.Build algR
+HB.instance Definition _ := Num.NumDomain_bounded_isArchimedean.Build algR
   algR_archiFieldMixin.
 
 Definition algRpfactor (x : algC) : {poly algR} :=