Figure 4: The Adjunctive Square Diagram-Brain Functors: A mathematical model of intentional perception and action

<p>Dually, we can define the above situation, given by the association of the sending universal G(A) with each object A in the receiving category along with the canonical isomorphism Het(X,A) &cong; Homsending(X,G(A)), as a right semiadjunction. Now we are prepared to define an adjunction essentially as:<br> adjunction = left semiadjunction + right semiadjunction Homreceiving(F(X),A) &cong; Het(X,A) &cong; Homsending(X,G(A)).</p>