You can't control prefixes and namespace declarations very well.

There are a few things you can do:

1. Declare the namespaces you want in your result document on the root element as well as the stylesheet element.

2. Use xsl:element with a prefix to copy elements from the input to the output:

   <xsl:template match="m:math">
   <xsl:element name="m:{local-name(.)}" namespace="{namespace-uri(.)}">
   <xsl:apply-templates select="@*|node()"/>
   </xsl:element>
   </xsl:template>

3. Use the exclude-result-prefixes attribute to exclude input and stylesheet prefix bindings.