(self, i)
return self.basic_root(i-1, i)
Every lie algebra has a unique root system.
        Given a root system Q, there is a subset of the
        roots such that an element of Q is called a
        simple root if it cannot be written as the sum
        of two elements in Q.  If we let D denote the
        set of simple roots, then it is clear that every
        element of Q can be written as a linear combination
        of elements of D with all coefficients non-negative.

        In A_n the ith simple root is the root which has a 1
        in the ith position, a -1 in the (i+1)th position,
        and zeroes elsewhere.

        This method returns the ith simple root for the A series.

        Examples
        ========

        >>> from sympy.liealgebras.cartan_type import CartanType
        >>> c = CartanType("A4")
        >>> c.simple_root(1)
        [1, -1, 0, 0, 0]
Every lie algebra has a unique root system.
        Given a root system Q, there is a subset of the
        roots such that an element of Q is called a
        simple root if it cannot be written as the sum
        of two elements in Q.  If we let D denote the
        set of simple roots, then it is clear that every
        element of Q can be written as a linear combination
        of elements of D with all coefficients non-negative.
Every lie algebra has a unique root system . Given a root system Q there is a subset of the roots such that an element of Q is called a simple root if it cannot be written as the sum of two elements in Q . If we let D denote the set of simple roots then it is clear that every element of Q can be written as a linear combination of elements of D with all coefficients non - negative .
def simple_root(self, i):
        """
        Every lie algebra has a unique root system.
        Given a root system Q, there is a subset of the
        roots such that an element of Q is called a
        simple root if it cannot be written as the sum
        of two elements in Q.  If we let D denote the
        set of simple roots, then it is clear that every
        element of Q can be written as a linear combination
        of elements of D with all coefficients non-negative.

        In A_n the ith simple root is the root which has a 1
        in the ith position, a -1 in the (i+1)th position,
        and zeroes elsewhere.

        This method returns the ith simple root for the A series.

        Examples
        ========

        >>> from sympy.liealgebras.cartan_type import CartanType
        >>> c = CartanType("A4")
        >>> c.simple_root(1)
        [1, -1, 0, 0, 0]

        """

        return self.basic_root(i-1, i)
def simple_root ( self , i ) : return self . basic_root ( i - 1 , i )