conversion

in linguistics, the formation of a new word from the transition of a given stem into another inflectional paradigm. For example, Russian pech’, “oven,” and pech’ “to bake,” and English love and (to) love are different parts of speech; in spite of external similarity, the base word and its derivative are different words, and the semantic relations between them may be diverse. The productivity of conversion is limited by the lexical significance of the stem and the structural peculiarities of the word.

in logic, the transformation of a sentence by changing the positions of its terms, the subject and predicate.

A conversion is said to be simple if quantifiers do not change when the sentence is converted. All negative propositions of the type “No S is P” and all particular affirmatives of the type “Some S are P” are converted simply. Universal affirmatives of the type “All S are P” are converted by limitation—that is, their conversions yield, generally speaking, a true sentence if the quantifier “all” is replaced by the quantifier “some.” Particular affirmatives of the type “Some S are not P” are not convertible: “Some smokers are not people” does not follow from “Some people do not smoke.”

In traditional logic, conversions were regarded as immediate inferences, which were placed in a special group. The rules governing them were formulated parallel’to the rules of syllogism. In modern predicate logic, conversion does not have independent meaning, and the rules of conversion per se are not included in the rules of logical deduction. This does not, however, diminish the heuristic value of conversion in logical thinking.

In the logic of relations, where every relation between the terms x and y has a corresponding concept about the relation between the terms y and x (the converse concept of the original relation), conversion involves replacing a given relation with its converse relation, while simultaneously transposing the terms of the relation.

in metallurgy, the treatment of metals that results in changes of chemical composition, physical and mechanical properties, and aggregation state; either all or some of these parameters may undergo a change. The first conversion is the production of pig iron from iron ore in blast furnaces; the second is the production of steel from pig iron; and the third is the working of metals by pressure to produce metallic articles of the desired shapes and sizes. Rolling, pressing, forging, and stamping are the basic types of pressure working. The fourth conversion is the aftertreatment of rolled metals; the term can refer to cold-rolling of strip and sheet metals, to profiling of strips, to sizing, and to drawing, as well as to the application of protective coatings and the production of metal ware.