There is no classification of the decidably presentable structures

There Is No Classification of the Decidably Presentable Structures

A computable structure A is decidable if, given a formula φ(x̄) of elementary first-order logic, and a tuple ā ∈ A, we have a decision procedure to decide whether φ holds of ā. We show that there is no reasonable classification of the decidably presentable structures. Formally, we show that the index set of the computable structures with decidable presentations is Σ1-complete. This result holds ...

There is no lexicon!

0. Introduction Within generative linguistics, underlying representations have been a sine qua non. Such representations have been thought to encode what is unpredictable or not governed by rules. Within Optimality Theory (henceforth OT), even though the rules are virtually gone, this view continues. The function GEN and EVAL pair an underlying representation with an optimal output. I argue aga...

the role of task-based techniques on the acquisition of english language structures by the intermediate efl students

this study examines the effetivenss of task-based activities in helping students learn english language structures for a better communication. initially, a michigan test was administered to the two groups of 52 students majoring in english at the allameh ghotb -e- ravandi university to ensure their homogeneity. the students scores on the grammar part of this test were also regarded as their pre...

There is no Parkinson disease.

The term Parkinson disease defines a specific clinical condition characterized by a typical history and characteristic signs. This review examines the historical evolution of the concept of Parkinson disease and how the misunderstanding of Parkinson disease may be hindering clinical research trials. It is proposed that this syndrome be called Parkinson diseases or parkinsonism type 1 through in...

There Is No Dividing Line