It has been observed quite early after the introduction of Tree Adjoining Grammars that the adjoining operation seems to be a special case of the more general deduction step in a context-free tree grammar (CFTG) derivation. TAGs look like special cases of a subclass of CFTGs, namely monadic linear CFTGs. More than a decade ago it was shown that the two grammar formalisms are indeed weakly equivalent, i.e., define the same classes of string languages. This paper now closes the remaining gap showing the strong equivalence for so-called non-strict TAGs, a variant of TAGs where the restrictions for head and foot nodes are slightly generalised.
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