# MV-1, MV-2, MV-3, MV-5
A i(x,i(y,x))
A i(i(x,y),i(i(y,z),i(x,z)))
A i(i(i(x,y),y),i(i(y,x),x))
A i(i(n(x),n(y)),i(y,x))
G i(n(n(x)),x)
G i(x,n(n(x)))