Linguistic errors are pervasive in second language (L2) students’ writing. Depending on their gravity, the errors may cause a minor degree of irritation to the reader or even lead to total communication breakdown. As such, errors have always been a major concern to both students and teachers, and error correction has also assumed a central position in language teaching. Students generally expec...

................................................................................................................................. iv INTRODUCTION AND LITERATURE REVIEW ..................................................................... 1 METHODS .................................................................................................................................. 24 RESULTS ..........

This paper develops a general technique to analyze the head reduction of a term in a context. This technique is used to give a direct proof of the theorem of Hyland and Wadsworth : two -terms that have the same Böhm trees, up to (possibly infinite) -equivalence, are operationally equivalent. It is also used to prove a conjecture of R. Kerth : Every unsolvable -term has a decoration. This syntac...

Motivated by some examples from functional programming, we propose a generalisation of the notion of trace to symmetric premonoidal categories and of Conway operators to Freyd categories. We show that, in a Freyd category, these notions are equivalent, generalising a well-known theorem of Hasegawa and Hyland.