Eductions-conversion, obversion, contraposition and Inverse

In Syllogistic logic, we generally draw conclusion from two premises. Since there are two or more premises and conclusion is drawn through more than one premise it is called Mediate Inference. Eduction is a form of Inference in which the conclusion is drawn from only one premise.  There are four main types of Eductions. They are Converse, Obverse, Contraposition and Inverse.

In a Converse Inference, the Subject and the Predicate of the statement are interchanged but the quality of the statement does not change. For example:

Statement: All dogs are cute 

Converse: Some cute things are dogs.

The above is an A proposition that becomes an I proposition in Conversion. 

E propositions remain E propositions. I propositions remain I propositions. O proposition Converse is not possible.

In Obverse Inference, the Subject and the Predicate remain the same as the statement but the quality is changed.

For example:

Statement: All dogs are cute

Obverse:  No dogs are non-cute.

The above is an A proposition that has changed to E proposition.

E propositions change to A propositions. I propositions change to O proposition. O propositions change to I propositions.

In Contraposition, a statement is changed to Obverse, then Converse and Obverse again.

In Inverse, one has to check whether one should follow Obverse-Converse-Obverse or Converse-Obverse-Converse.