how to split element value and assign those value with new element tag name in xslt

my input xml:

  The existence of a globally hyperbolic Lorentzian metric on a 

  <mml:math>(3 + 1)</mml:math>

 -spacetime with closed Cauchy surface excludes all but one differentiable structure on the underlying manifold, as observed by ChernovNemirovski 

[

<no>

   CN13

</no>

<id>

   CN

 ]

We point out in this note that the diffeomorphism type of a globally hyperbolic 

(n+ 1)

-spacetime is determined by the h-cobordism class of its closed Cauchy surface. The precise statement is as follows.

my xslt is;

  <xsl:apply-templates select="body/ce:para"/>

 <xsl:value-of select="ce:para/text[1]"/>

 <mml:mo stretchy="false">(</mml:mo>

  <mml:mn>

 <xsl:value-of select="translate(substring-after(substring-before(mml:math,'+'),'('),' ','')"/>

</mml:mn>

<mml:mo>

<xsl:text>+</xsl:text>

</mml:mo>

<mml:mn>

<xsl:value-of select="translate(substring-before(substring-after(mml:math,'+'),')'),' 

','')"/>

</mml:mn>

<mml:mo stretchy="false">)</mml:mo>

<mml:mo stretchy="false">(</mml:mo>

+

)

my expected output xml:

The existence of a globally hyperbolic Lorentzian metric on a

(

3

+

1

)

</mml:math>

-spacetime with closed Cauchy surface excludes all but one differentiable structure on the underlying manifold, as observed by Chernov–Nemirovski 

[CN13].

We point out in this note that the diffeomorphism type of a globally hyperbolic

(

n

+

1

)

-spacetime is determined by the h-cobordism class of its closed Cauchy surface. The precise statement is as follows.