diff --git a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/ListRationalFunction.kt b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/ListRationalFunction.kt
index 45ea99fb0..f3e352bcd 100644
--- a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/ListRationalFunction.kt
+++ b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/ListRationalFunction.kt
@@ -50,15 +50,6 @@ public class ListRationalFunctionSpace<C, A : Ring<C>> (
     override fun constructRationalFunction(numerator: ListPolynomial<C>, denominator: ListPolynomial<C>): ListRationalFunction<C> =
         ListRationalFunction(numerator, denominator)
 
-    /**
-     * Instance of zero rational function (zero of the rational functions ring).
-     */
-    public override val zero: ListRationalFunction<C> = ListRationalFunction(polynomialZero, polynomialOne)
-    /**
-     * Instance of unit polynomial (unit of the rational functions ring).
-     */
-    public override val one: ListRationalFunction<C> = ListRationalFunction(polynomialOne, polynomialOne)
-
     // TODO: When context receivers will be ready move all of this substitutions and invocations to utilities with
     //  [ListPolynomialSpace] as a context receiver
     /**
diff --git a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/RationalFunction.kt b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/RationalFunction.kt
index 4ce6c7c26..01911f980 100644
--- a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/RationalFunction.kt
+++ b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/RationalFunction.kt
@@ -834,7 +834,12 @@ public abstract class PolynomialSpaceOfFractions<
             numerator * other,
             denominator
         )
-
+    /**
+     * Returns quotient of the rational function and the integer represented as a rational function.
+     *
+     * The operation is equivalent to creating a new rational function by preserving numerator of [this] and
+     * multiplication denominator of [this] to [other].
+     */
     public override operator fun R.div(other: Int): R =
         constructRationalFunction(
             numerator,
@@ -871,7 +876,12 @@ public abstract class PolynomialSpaceOfFractions<
             this * other.numerator,
             other.denominator
         )
-
+    /**
+     * Returns quotient of the integer represented as a rational function and the rational function.
+     *
+     * The operation is equivalent to creating a new rational function which numerator is [this] times denominator of
+     * [other] and which denominator is [other]'s numerator.
+     */
     public override operator fun Int.div(other: R): R =
         constructRationalFunction(
             this * other.denominator,
@@ -912,7 +922,9 @@ public abstract class PolynomialSpaceOfFractions<
             this * other.numerator,
             other.denominator
         )
-
+    /**
+     * Returns quotient of the constant represented as a polynomial and the rational function.
+     */
     public override operator fun C.div(other: R): R =
         constructRationalFunction(
             this * other.denominator,
@@ -943,7 +955,9 @@ public abstract class PolynomialSpaceOfFractions<
             numerator * other,
             denominator
         )
-
+    /**
+     * Returns quotient of the rational function and the constant represented as a rational function.
+     */
     public override operator fun R.div(other: C): R =
         constructRationalFunction(
             numerator,
@@ -979,7 +993,9 @@ public abstract class PolynomialSpaceOfFractions<
             this * other.numerator,
             other.denominator
         )
-
+    /**
+     * Returns quotient of the polynomial represented as a polynomial and the rational function.
+     */
     public override operator fun P.div(other: R): R =
         constructRationalFunction(
             this * other.denominator,
@@ -1010,7 +1026,9 @@ public abstract class PolynomialSpaceOfFractions<
             numerator * other,
             denominator
         )
-
+    /**
+     * Returns quotient of the rational function and the polynomial represented as a rational function.
+     */
     public override operator fun R.div(other: P): R =
         constructRationalFunction(
             numerator,
@@ -1050,7 +1068,9 @@ public abstract class PolynomialSpaceOfFractions<
             numerator * other.numerator,
             denominator * other.denominator
         )
-
+    /**
+     * Returns quotient of the rational functions.
+     */
     public override operator fun R.div(other: R): R =
         constructRationalFunction(
             numerator * other.denominator,
diff --git a/kmath-functions/src/commonTest/kotlin/space/kscience/kmath/test/misc/IntModulo.kt b/kmath-functions/src/commonTest/kotlin/space/kscience/kmath/test/misc/IntModulo.kt
index 36a0d8be5..89764db46 100644
--- a/kmath-functions/src/commonTest/kotlin/space/kscience/kmath/test/misc/IntModulo.kt
+++ b/kmath-functions/src/commonTest/kotlin/space/kscience/kmath/test/misc/IntModulo.kt
@@ -7,7 +7,6 @@ package space.kscience.kmath.test.misc
 
 import space.kscience.kmath.functions.ListPolynomial
 import space.kscience.kmath.functions.ListPolynomialSpace
-import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.operations.Ring
 
 
@@ -109,7 +108,6 @@ class IntModulo {
 }
 
 @Suppress("EXTENSION_SHADOWED_BY_MEMBER", "OVERRIDE_BY_INLINE", "NOTHING_TO_INLINE")
-@OptIn(UnstableKMathAPI::class)
 class IntModuloRing : Ring<IntModulo> {
 
     val modulus: Int