diff --git a/kmath-ast/src/commonMain/kotlin/kscience/kmath/ast/MstAlgebra.kt b/kmath-ast/src/commonMain/kotlin/kscience/kmath/ast/MstAlgebra.kt
index 64a820b20..9c58043dd 100644
--- a/kmath-ast/src/commonMain/kotlin/kscience/kmath/ast/MstAlgebra.kt
+++ b/kmath-ast/src/commonMain/kotlin/kscience/kmath/ast/MstAlgebra.kt
@@ -6,14 +6,14 @@ import kscience.kmath.operations.*
  * [Algebra] over [MST] nodes.
  */
 public object MstAlgebra : NumericAlgebra<MST> {
-    override fun number(value: Number): MST = MST.Numeric(value)
+    override fun number(value: Number): MST.Numeric = MST.Numeric(value)
 
-    override fun symbol(value: String): MST = MST.Symbolic(value)
+    override fun symbol(value: String): MST.Symbolic = MST.Symbolic(value)
 
-    override fun unaryOperation(operation: String, arg: MST): MST =
+    override fun unaryOperation(operation: String, arg: MST): MST.Unary =
         MST.Unary(operation, arg)
 
-    override fun binaryOperation(operation: String, left: MST, right: MST): MST =
+    override fun binaryOperation(operation: String, left: MST, right: MST): MST.Binary =
         MST.Binary(operation, left, right)
 }
 
@@ -21,97 +21,102 @@ public object MstAlgebra : NumericAlgebra<MST> {
  * [Space] over [MST] nodes.
  */
 public object MstSpace : Space<MST>, NumericAlgebra<MST> {
-    override val zero: MST = number(0.0)
+    public override val zero: MST.Numeric by lazy { number(0.0) }
 
-    override fun number(value: Number): MST = MstAlgebra.number(value)
-    override fun symbol(value: String): MST = MstAlgebra.symbol(value)
-    override fun add(a: MST, b: MST): MST = binaryOperation(SpaceOperations.PLUS_OPERATION, a, b)
-    override fun multiply(a: MST, k: Number): MST = binaryOperation(RingOperations.TIMES_OPERATION, a, number(k))
+    public override fun number(value: Number): MST.Numeric = MstAlgebra.number(value)
+    public override fun symbol(value: String): MST.Symbolic = MstAlgebra.symbol(value)
+    public override fun add(a: MST, b: MST): MST.Binary = binaryOperation(SpaceOperations.PLUS_OPERATION, a, b)
 
-    override fun binaryOperation(operation: String, left: MST, right: MST): MST =
+    public override fun multiply(a: MST, k: Number): MST.Binary =
+        binaryOperation(RingOperations.TIMES_OPERATION, a, number(k))
+
+    public override fun binaryOperation(operation: String, left: MST, right: MST): MST.Binary =
         MstAlgebra.binaryOperation(operation, left, right)
 
-    override fun unaryOperation(operation: String, arg: MST): MST = MstAlgebra.unaryOperation(operation, arg)
+    public override fun unaryOperation(operation: String, arg: MST): MST.Unary = MstAlgebra.unaryOperation(operation, arg)
 }
 
 /**
  * [Ring] over [MST] nodes.
  */
 public object MstRing : Ring<MST>, NumericAlgebra<MST> {
-    override val zero: MST
+    public override val zero: MST.Numeric
         get() = MstSpace.zero
-    override val one: MST = number(1.0)
 
-    override fun number(value: Number): MST = MstSpace.number(value)
-    override fun symbol(value: String): MST = MstSpace.symbol(value)
-    override fun add(a: MST, b: MST): MST = MstSpace.add(a, b)
+    public override val one: MST.Numeric by lazy { number(1.0) }
 
-    override fun multiply(a: MST, k: Number): MST = MstSpace.multiply(a, k)
+    public override fun number(value: Number): MST.Numeric = MstSpace.number(value)
+    public override fun symbol(value: String): MST.Symbolic = MstSpace.symbol(value)
+    public override fun add(a: MST, b: MST): MST.Binary = MstSpace.add(a, b)
+    public override fun multiply(a: MST, k: Number): MST.Binary = MstSpace.multiply(a, k)
+    public override fun multiply(a: MST, b: MST): MST.Binary = binaryOperation(RingOperations.TIMES_OPERATION, a, b)
 
-    override fun multiply(a: MST, b: MST): MST = binaryOperation(RingOperations.TIMES_OPERATION, a, b)
-
-    override fun binaryOperation(operation: String, left: MST, right: MST): MST =
+    public override fun binaryOperation(operation: String, left: MST, right: MST): MST.Binary =
         MstSpace.binaryOperation(operation, left, right)
 
-    override fun unaryOperation(operation: String, arg: MST): MST = MstAlgebra.unaryOperation(operation, arg)
+    public override fun unaryOperation(operation: String, arg: MST): MST.Unary = MstSpace.unaryOperation(operation, arg)
 }
 
 /**
  * [Field] over [MST] nodes.
  */
 public object MstField : Field<MST> {
-    public override val zero: MST
+    public override val zero: MST.Numeric
         get() = MstRing.zero
 
-    public override val one: MST
+    public override val one: MST.Numeric
         get() = MstRing.one
 
-    public override fun symbol(value: String): MST = MstRing.symbol(value)
-    public override fun number(value: Number): MST = MstRing.number(value)
-    public override fun add(a: MST, b: MST): MST = MstRing.add(a, b)
-    public override fun multiply(a: MST, k: Number): MST = MstRing.multiply(a, k)
-    public override fun multiply(a: MST, b: MST): MST = MstRing.multiply(a, b)
-    public override fun divide(a: MST, b: MST): MST = binaryOperation(FieldOperations.DIV_OPERATION, a, b)
+    public override fun symbol(value: String): MST.Symbolic = MstRing.symbol(value)
+    public override fun number(value: Number): MST.Numeric = MstRing.number(value)
+    public override fun add(a: MST, b: MST): MST.Binary = MstRing.add(a, b)
+    public override fun multiply(a: MST, k: Number): MST.Binary = MstRing.multiply(a, k)
+    public override fun multiply(a: MST, b: MST): MST.Binary = MstRing.multiply(a, b)
+    public override fun divide(a: MST, b: MST): MST.Binary = binaryOperation(FieldOperations.DIV_OPERATION, a, b)
 
-    public override fun binaryOperation(operation: String, left: MST, right: MST): MST =
+    public override fun binaryOperation(operation: String, left: MST, right: MST): MST.Binary =
         MstRing.binaryOperation(operation, left, right)
 
-    override fun unaryOperation(operation: String, arg: MST): MST = MstRing.unaryOperation(operation, arg)
+    public override fun unaryOperation(operation: String, arg: MST): MST.Unary = MstRing.unaryOperation(operation, arg)
 }
 
 /**
  * [ExtendedField] over [MST] nodes.
  */
 public object MstExtendedField : ExtendedField<MST> {
-    override val zero: MST
+    public override val zero: MST.Numeric
         get() = MstField.zero
 
-    override val one: MST
+    public override val one: MST.Numeric
         get() = MstField.one
 
-    override fun symbol(value: String): MST = MstField.symbol(value)
-    override fun sin(arg: MST): MST = unaryOperation(TrigonometricOperations.SIN_OPERATION, arg)
-    override fun cos(arg: MST): MST = unaryOperation(TrigonometricOperations.COS_OPERATION, arg)
-    override fun tan(arg: MST): MST = unaryOperation(TrigonometricOperations.TAN_OPERATION, arg)
-    override fun asin(arg: MST): MST = unaryOperation(TrigonometricOperations.ASIN_OPERATION, arg)
-    override fun acos(arg: MST): MST = unaryOperation(TrigonometricOperations.ACOS_OPERATION, arg)
-    override fun atan(arg: MST): MST = unaryOperation(TrigonometricOperations.ATAN_OPERATION, arg)
-    override fun sinh(arg: MST): MST = unaryOperation(HyperbolicOperations.SINH_OPERATION, arg)
-    override fun cosh(arg: MST): MST = unaryOperation(HyperbolicOperations.COSH_OPERATION, arg)
-    override fun tanh(arg: MST): MST = unaryOperation(HyperbolicOperations.TANH_OPERATION, arg)
-    override fun asinh(arg: MST): MST = unaryOperation(HyperbolicOperations.ASINH_OPERATION, arg)
-    override fun acosh(arg: MST): MST = unaryOperation(HyperbolicOperations.ACOSH_OPERATION, arg)
-    override fun atanh(arg: MST): MST = unaryOperation(HyperbolicOperations.ATANH_OPERATION, arg)
-    override fun add(a: MST, b: MST): MST = MstField.add(a, b)
-    override fun multiply(a: MST, k: Number): MST = MstField.multiply(a, k)
-    override fun multiply(a: MST, b: MST): MST = MstField.multiply(a, b)
-    override fun divide(a: MST, b: MST): MST = MstField.divide(a, b)
-    override fun power(arg: MST, pow: Number): MST = binaryOperation(PowerOperations.POW_OPERATION, arg, number(pow))
-    override fun exp(arg: MST): MST = unaryOperation(ExponentialOperations.EXP_OPERATION, arg)
-    override fun ln(arg: MST): MST = unaryOperation(ExponentialOperations.LN_OPERATION, arg)
+    public override fun symbol(value: String): MST.Symbolic = MstField.symbol(value)
+    public override fun number(value: Number): MST.Numeric = MstField.number(value)
+    public override fun sin(arg: MST): MST.Unary = unaryOperation(TrigonometricOperations.SIN_OPERATION, arg)
+    public override fun cos(arg: MST): MST.Unary = unaryOperation(TrigonometricOperations.COS_OPERATION, arg)
+    public override fun tan(arg: MST): MST.Unary = unaryOperation(TrigonometricOperations.TAN_OPERATION, arg)
+    public override fun asin(arg: MST): MST.Unary = unaryOperation(TrigonometricOperations.ASIN_OPERATION, arg)
+    public override fun acos(arg: MST): MST.Unary = unaryOperation(TrigonometricOperations.ACOS_OPERATION, arg)
+    public override fun atan(arg: MST): MST.Unary = unaryOperation(TrigonometricOperations.ATAN_OPERATION, arg)
+    public override fun sinh(arg: MST): MST.Unary = unaryOperation(HyperbolicOperations.SINH_OPERATION, arg)
+    public override fun cosh(arg: MST): MST.Unary = unaryOperation(HyperbolicOperations.COSH_OPERATION, arg)
+    public override fun tanh(arg: MST): MST.Unary = unaryOperation(HyperbolicOperations.TANH_OPERATION, arg)
+    public override fun asinh(arg: MST): MST.Unary = unaryOperation(HyperbolicOperations.ASINH_OPERATION, arg)
+    public override fun acosh(arg: MST): MST.Unary = unaryOperation(HyperbolicOperations.ACOSH_OPERATION, arg)
+    public override fun atanh(arg: MST): MST.Unary = unaryOperation(HyperbolicOperations.ATANH_OPERATION, arg)
+    public override fun add(a: MST, b: MST): MST.Binary = MstField.add(a, b)
+    public override fun multiply(a: MST, k: Number): MST.Binary = MstField.multiply(a, k)
+    public override fun multiply(a: MST, b: MST): MST.Binary = MstField.multiply(a, b)
+    public override fun divide(a: MST, b: MST): MST.Binary = MstField.divide(a, b)
 
-    override fun binaryOperation(operation: String, left: MST, right: MST): MST =
+    public override fun power(arg: MST, pow: Number): MST.Binary =
+        binaryOperation(PowerOperations.POW_OPERATION, arg, number(pow))
+
+    public override fun exp(arg: MST): MST.Unary = unaryOperation(ExponentialOperations.EXP_OPERATION, arg)
+    public override fun ln(arg: MST): MST.Unary = unaryOperation(ExponentialOperations.LN_OPERATION, arg)
+
+    public override fun binaryOperation(operation: String, left: MST, right: MST): MST.Binary =
         MstField.binaryOperation(operation, left, right)
 
-    override fun unaryOperation(operation: String, arg: MST): MST = MstField.unaryOperation(operation, arg)
+    public override fun unaryOperation(operation: String, arg: MST): MST.Unary = MstField.unaryOperation(operation, arg)
 }
diff --git a/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Complex.kt b/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Complex.kt
index e9bd3ac2b..b242c8b0f 100644
--- a/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Complex.kt
+++ b/kmath-core/src/commonMain/kotlin/kscience/kmath/operations/Complex.kt
@@ -111,7 +111,7 @@ public object ComplexField : ExtendedField<Complex>, Norm<Complex, Complex> {
     public override operator fun Complex.plus(b: Number): Complex = b + this
     public override operator fun Complex.minus(b: Number): Complex = add(this, -b.toComplex())
     public override operator fun Number.times(b: Complex): Complex = Complex(b.re * toDouble(), b.im * toDouble())
-    public override fun Complex.unaryMinus(): Complex = Complex(-re, -im)
+    public override operator fun Complex.unaryMinus(): Complex = Complex(-re, -im)
     public override fun norm(arg: Complex): Complex = sqrt(arg.conjugate * arg)
     public override fun symbol(value: String): Complex = if (value == "i") i else super.symbol(value)
 }
diff --git a/kmath-core/src/commonMain/kotlin/kscience/kmath/structures/MemoryBuffer.kt b/kmath-core/src/commonMain/kotlin/kscience/kmath/structures/MemoryBuffer.kt
index 66c9212cf..3a98ce941 100644
--- a/kmath-core/src/commonMain/kotlin/kscience/kmath/structures/MemoryBuffer.kt
+++ b/kmath-core/src/commonMain/kotlin/kscience/kmath/structures/MemoryBuffer.kt
@@ -43,8 +43,8 @@ public class MutableMemoryBuffer<T : Any>(memory: Memory, spec: MemorySpec<T>) :
 
     private val writer: MemoryWriter = memory.writer()
 
-    override operator fun set(index: Int, value: T): Unit = writer.write(spec, spec.objectSize * index, value)
-    override fun copy(): MutableBuffer<T> = MutableMemoryBuffer(memory.copy(), spec)
+    public override operator fun set(index: Int, value: T): Unit = writer.write(spec, spec.objectSize * index, value)
+    public override fun copy(): MutableBuffer<T> = MutableMemoryBuffer(memory.copy(), spec)
 
     public companion object {
         public fun <T : Any> create(spec: MemorySpec<T>, size: Int): MutableMemoryBuffer<T> =