diff --git a/_CoqProject b/_CoqProject
index 1caabc13..859e6f2e 100644
--- a/_CoqProject
+++ b/_CoqProject
@@ -95,4 +95,7 @@ toy_examples/expected_value_variance_ordn.v
 toy_examples/expected_value_variance_tuple.v
 toy_examples/conditional_entropy.v
 
+# temporary files for migration to mca real
+probability/proba_mcreal.v
+
 -R . infotheo
diff --git a/probability/proba_mcreal.v b/probability/proba_mcreal.v
new file mode 100644
index 00000000..35bcb935
--- /dev/null
+++ b/probability/proba_mcreal.v
@@ -0,0 +1,129 @@
+(* infotheo: information theory and error-correcting codes in Coq             *)
+(* Copyright (C) 2020 infotheo authors, license: LGPL-2.1-or-later            *)
+From mathcomp Require Import all_ssreflect ssralg ssrnum matrix.
+From mathcomp Require boolp.
+From mathcomp Require Import Rstruct reals.
+Require Import Reals Lra.
+Require Import ssrR Reals_ext realType_ext logb ssr_ext ssralg_ext.
+Require Import bigop_ext fdist proba.
+
+(* from mca master *)
+Local Lemma Pos_to_natE p : Pos.to_nat p = nat_of_pos p.
+Proof.
+by elim: p => //= p <-;
+  rewrite ?(Pnat.Pos2Nat.inj_xI,Pnat.Pos2Nat.inj_xO) NatTrec.doubleE -mul2n.
+Qed.
+Local Lemma IZRposE (p : positive) : IZR (Z.pos p) = INR (nat_of_pos p).
+Proof. by rewrite -Pos_to_natE INR_IPR. Qed.
+Local Definition coqRE := (IZRposE, coqRE).
+
+(* TODO: update proba.v to use mcR *)
+Lemma Ex_ge0 (U : finType) (P : {fdist U})
+  (X : {RV P -> R}) : (forall u : U, 0 <= X u) -> 0 <= `E X.
+Proof. by move=> H; apply/RleP/Ex_ge0=> u; apply/RleP/H. Qed.
+Lemma sq_RV_ge0 (U : finType) (P : {fdist U})
+  (X : {RV (P) -> (R)}) (x : U) : 0 <= (X `^2) x.
+Proof. exact/RleP/sq_RV_ge0. Qed.
+Lemma Pr_lt1 (A : finType) (P : R.-fdist A) (E : {set A}) :
+  Pr P E < 1 <-> Pr P E != 1.
+Proof. by rewrite -(rwP (RltP (Pr P E) 1)) Pr_lt1. Qed.
+Lemma Pr_gt0 (A : finType) (P : R.-fdist A) (E : {set A}) :
+  0 < Pr P E <-> Pr P E != 0.
+Proof. by rewrite -(rwP (RltP 0 (Pr P E))) Pr_gt0. Qed.
+Lemma Pr_ge0 (A : finType) (P : R.-fdist A) (E : {set A}) : 0 <= Pr P E.
+Proof. by exact/RleP/Pr_ge0. Qed.
+(* should be Pr_subset? *)
+Lemma Pr_incl (A : finType) (P : R.-fdist A) (E E' : {set A}) :
+  E \subset E' -> Pr P E <= Pr P E'.
+Proof. by move/Pr_incl=> ?; exact/RleP. Qed.
+(* should be Pr_setC? *)
+Lemma Pr_of_cplt (A : finType) (P : R.-fdist A) (E : {set A}) :
+  Pr P (~: E) = 1 - Pr P E.
+Proof. exact: Pr_of_cplt. Qed.
+Lemma Pr_to_cplt (A : finType) (P : R.-fdist A) (E : {set A}) :
+  Pr P E = 1 - Pr P (~: E).
+Proof. exact: Pr_to_cplt. Qed.
+(* should be Pr_setD? *)
+Lemma Pr_diff (A : finType) (P : R.-fdist A) (E1 E2 : {set A}) :
+  Pr P (E1 :\: E2) = Pr P E1 - Pr P (E1 :&: E2).
+Proof. exact: Pr_diff. Qed.
+(* should be Pr_add_setC (or PrDsetC)? *)
+Lemma Pr_cplt (A : finType) (P : R.-fdist A) (E : {set A}) :
+  Pr P E + Pr P (~: E) = 1.
+Proof. exact: Pr_cplt. Qed.
+(* should be Pr_setI? *)
+Lemma Pr_inter_eq (A : finType) (P : R.-fdist A) (E1 E2 : {set A}) :
+  Pr P (E1 :&: E2) = Pr P E1 + Pr P E2 - Pr P (E1 :|: E2).
+Proof. exact: Pr_inter_eq. Qed.
+(* should be Pr_setU? *)
+Lemma Pr_union_eq (A : finType) (P : R.-fdist A) (E1 E2 : {set A}) :
+  Pr P (E1 :|: E2) = Pr P E1 + Pr P E2 - Pr P (E1 :&: E2).
+Proof. exact: Pr_union_eq. Qed.
+(* should be Pr_setU_disj (or Pr_disjU)? *)
+Lemma Pr_union_disj (A : finType) (P : R.-fdist A) (E1 E2 : {set A}) :
+  [disjoint E1 & E2] -> Pr P (E1 :|: E2) = Pr P E1 + Pr P E2.
+Proof. exact: Pr_union_disj. Qed.
+(* should be Pr_eq0P *)
+Lemma Pr_set0P (A : finType) (P : R.-fdist A) (E : {set A}) :
+  Pr P E = 0 <-> (forall a : A, a \in E -> P a = 0).
+Proof. exact: Pr_set0P. Qed.
+Lemma E_sub_RV (U : finType) (P : R.-fdist U) (X Y : {RV (P) -> (R)}) :
+  `E (X `- Y) = `E X - `E Y.
+Proof. exact: E_sub_RV. Qed.
+Lemma E_add_RV (U : finType) (P : R.-fdist U) (X Y : {RV (P) -> (R)}) :
+  `E (X `+ Y) = `E X + `E Y.
+Proof. exact: E_add_RV. Qed.
+Lemma E_scalel_RV (U : finType) (P : R.-fdist U) (X : {RV (P) -> (R)})
+  (k : R) : `E (k `cst* X) = k * `E X.
+Proof. exact: E_scalel_RV. Qed.
+
+(* TODO: define RV_ringType mimicking fct_ringType *)
+Section mul_RV.
+Variables (U : finType) (P : {fdist U}).
+Definition mul_RV (X Y : {RV P -> R}) : {RV P -> R} := fun x => X x * Y x.
+Notation "X `* Y" := (mul_RV X Y) : proba_scope.
+Arguments mul_RV /.
+Lemma mul_RVA : associative mul_RV.
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite mulrA. Qed.
+Lemma mul_RVC : commutative mul_RV.
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite mulrC. Qed.
+Lemma mul_RVAC : right_commutative mul_RV.
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite mulrAC. Qed.
+Lemma mul_RVCA : left_commutative mul_RV.
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite mulrCA. Qed.
+Lemma mul_RVACA : interchange mul_RV mul_RV.
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite mulrACA. Qed.
+Lemma mul_RVDr : right_distributive mul_RV (@add_RV U P).
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite mulrDr. Qed.
+Lemma mul_RVDl : left_distributive mul_RV (@add_RV U P).
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite mulrDl. Qed.
+Lemma mul_RVBr (f g h : {RV (P) -> (R)}) : f `* (g `- h) = f `* g `- f `* h.
+Proof. by apply: boolp.funext=> u /=; rewrite mulrBr. Qed.
+Lemma mul_RVBl (f g h : {RV (P) -> (R)}) : (f `- g) `* h = f `* h `- g `* h.
+Proof. by apply: boolp.funext=> u /=; rewrite mulrBl. Qed.
+End mul_RV.
+Notation "X `* Y" := (mul_RV X Y) : proba_scope.
+Arguments mul_RV /.
+
+Section add_RV.
+Variables (U : finType) (P : {fdist U}).
+Arguments add_RV /.
+Lemma add_RVA : associative (@add_RV U P).
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite addRA. Qed.
+Lemma add_RVC : commutative (@add_RV U P).
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite addRC. Qed.
+Lemma add_RVAC : right_commutative (@add_RV U P).
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite addRAC. Qed.
+Lemma add_RVCA : left_commutative (@add_RV U P).
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite addRCA. Qed.
+Lemma add_RVACA : interchange (@add_RV U P) (@add_RV U P).
+Proof. by move=> *; apply: boolp.funext=> u /=; rewrite !coqRE addrACA. Qed.
+End add_RV.
+
+Section scalelr.
+Variables (U : finType) (P : {fdist U}).
+Lemma scalel_RVE m (X : {RV P -> R}) : scalel_RV m X = const_RV P m `* X.
+Proof. by apply: boolp.funext=> ? /=; rewrite /scalel_RV /const_RV !coqRE. Qed.
+Lemma scaler_RVE m (X : {RV P -> R}) : scaler_RV X m = X `* const_RV P m.
+Proof. by apply: boolp.funext=> ? /=; rewrite /scaler_RV /const_RV !coqRE. Qed.
+End scalelr.