Logic
	
	

	

	

        

            
            0
            1
        

        

            > a
            ab
            a
        

        

             b
            c
            ϕ
        

        

            * c
            ϕ
            ϕ
        

    

	

        

            
            0
            1
        

        

            > A
            B
            A
        

        

             B
            C
            A
        

        

            * C
            C
            A