Improve documentation

kmath-core/src/commonMain/kotlin/scientifik/kmath/operations/AlgebraElements.kt

@@ -24,9 +24,36 @@ interface MathWrapper<T, I> {
  * @param S the type of space
  */
 interface SpaceElement<T, I : SpaceElement<T, I, S>, S : Space<T>> : MathElement<S>, MathWrapper<T, I> {
+    /**
+     * Adds element to this one.
+     *
+     * @param b the augend.
+     * @return the sum.
+     */
     operator fun plus(b: T): I = context.add(unwrap(), b).wrap()
+
+    /**
+     * Subtracts element from this one.
+     *
+     * @param b the subtrahend.
+     * @return the difference.
+     */
     operator fun minus(b: T): I = context.add(unwrap(), context.multiply(b, -1.0)).wrap()
+
+    /**
+     * Multiplies this element by number.
+     *
+     * @param k the multiplicand.
+     * @return the product.
+     */
     operator fun times(k: Number): I = context.multiply(unwrap(), k.toDouble()).wrap()
+
+    /**
+     * Divides this element by number.
+     *
+     * @param k the divisor.
+     * @return the quotient.
+     */
     operator fun div(k: Number): I = context.multiply(unwrap(), 1.0 / k.toDouble()).wrap()
 }
 
@@ -34,6 +61,12 @@ interface SpaceElement<T, I : SpaceElement<T, I, S>, S : Space<T>> : MathElement
  * Ring element
  */
 interface RingElement<T, I : RingElement<T, I, R>, R : Ring<T>> : SpaceElement<T, I, R> {
+    /**
+     * Multiplies this element by another one.
+     *
+     * @param b the multiplicand.
+     * @return the product.
+     */
     operator fun times(b: T): I = context.multiply(unwrap(), b).wrap()
 }
 
@@ -42,5 +75,12 @@ interface RingElement<T, I : RingElement<T, I, R>, R : Ring<T>> : SpaceElement<T
  */
 interface FieldElement<T, I : FieldElement<T, I, F>, F : Field<T>> : RingElement<T, I, F> {
     override val context: F
+
+    /**
+     * Divides this element by another one.
+     *
+     * @param b the divisor.
+     * @return the quotient.
+     */
     operator fun div(b: T): I = context.divide(unwrap(), b).wrap()
 }