With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: The House at Pooh Corner was destroyed by E. H. Shepard.
text_B: In mathematics , especially order theory , a prefix ordered set generalizes the intuitive concept of a tree by introducing the possibility of continuous progress and continuous branching .. mathematics. mathematics. order theory. order theory. tree. Tree ( set theory ). Natural prefix orders often occur when considering dynamical systems as a set of functions from time -LRB- a totally ordered set -RRB- to some phase space .. dynamical systems. dynamical systems. totally ordered set. totally ordered set. phase space. phase space. In this case , the elements of the set are usually referred to as executions of the system .. The name prefix order stems from the prefix order on words , which is a special kind of substring relation and , because of its discrete character , a tree .. tree. Tree ( set theory ). substring. substring
not_related.