[MUSIC] Lexical cohesion is the cohesive effect achieved by the selection of vocabulary. Lexical cohesion is basically created by the general nouns, or repetition of the same lexeme, or the use of other lexical relations as cohesive patterns. Lexical cohesion refers to the ties created between lexical elements, such as words. For example, mechanics, or groups of words. Quantum mechanics and phrases to carry out research. These lexical ties can occur over long passages of text or discourse. The primary paradigmatic types of cohesion, meaning words of the same type of class, are repetition, synonymy hyponymy and meronymy. Repetition means using the same word over again, but not restricting to the same morphological form. In this short example the author repeats the word motion four times. Synonymy: using words that are in the same way synonymous, or, in the case of autonomy, in some way autonomous. The word study and research, they are synonyms. Hyponymy: one word represents "a class of thing and the second either a superclass or a subclass, or another class of the same level. For example, Spark Plasma Sintering is a class of thing, while techniques is a sub-class. Meronymy: words that refer to parts of a whole. For example, research. That's class, experiment, observations, procedure, sampling. One of the practical tools that can help improve the lexical coherence of your writing, is to use a concept map. There is a different type of lexical coherence that occurs at stigmatic level, the level of syntax. General nouns: in this type of cohesion, two items have the same referent. Military actions against Iraq were not successful. The moves were illegal. The class of general noun, is a small set of nouns having generalized reference within the major noun class, such as human noun, place noun, fact noun. Cohesive nouns are a kind of lexical reference. They can summarize many words in one. Attitude, solution, difficulty, and have been called umbrella nouns for this reason. They are used to signal what is to come. For example, the problem to be discuss, or can refer back. The issue. Over a million dollars was spent last year. This investment was needed and was wisely spent. Cohesion occurs when the interpretation of some element in the discourse, is dependent on that of another. Collocation: referring to the tendency of words to occur. For example, when one says the now in a search of a sentence. It is more probable that the verb to conduct will also appear in the same sentence. In another example, the noun figure, could more likely occur with a verb to indicate. Often lexical cohesion occurs, not simply between parts of words, but over a succession of a number of nearby related words, spanning a topical unit of the text. This lexical cohesion sequences of related words will be called Lexical chains. Here is a distance relation between each word and the chain. But the words co-occur within a given span. Lexical chains do not stop at sentence boundaries. They can connect the part of adjacent words or range over an entire text. Lexical chains tend to delineate portions of text that have a strong unity of meaning. Consider this example. Bizarrely behaving light particles show that the famous Schrodinger's cat thought experiment, meant to reveal the strange nature of subatomic particles, can get even weirder than physicists thought. Why are lexical chains important? First, they provide an easy-to-determine context, to aid in the resolution of ambiguity, and then the narrowing to specific meaning of a word. Second, Lexical chains provide a clue for the determination of coherence and discourse structure, and hence the larger meaning of the text. When a chunk of text forms a unit within a discourse there is a tendency for related words to be used. It follows, that if lexical chains can be determined, they will tend to indicated the structure of the whole text.