PREFIX  vg:   <http://example.org/vg/>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

SELECT DISTINCT ?path_A ?pathSeq_A ?path_B ?pathSeq_B {
    {
    SELECT  (?path AS ?path_A) (GROUP_CONCAT(?sequence ; SEPARATOR='') AS ?pathSeq_A)
    WHERE
      { ?step  vg:path    ?path ;
               vg:node    ?node ;
               vg:rank    ?rank .
        ?node  rdf:value  ?sequence
      }
    GROUP BY ?path
    ORDER BY ASC(MAX(?rank))
    }

    {
    SELECT (?path AS ?path_B) (GROUP_CONCAT(?sequence ; SEPARATOR='') AS ?pathSeq_B)
    WHERE
      { ?step  vg:path    ?path ;
               vg:node    ?node ;
               vg:rank    ?rank .
        ?node  rdf:value  ?sequence
      }
    GROUP BY ?path
    ORDER BY ASC(MAX(?rank))

    }
}