Greetings.

In Fulton's 'Introduction to Toric Varieties' in section 2.5, there is an exercise (top of p44 in my book) which reads 'If $d \geq 4$ then there must be 2 opposite vectors in the sequence'.

Is this a typo? For example, is there a problem with the seqence $(1,0),(1,1),(0,1),(-1,1)$? If it is a typo, does replacing 4 with 5 make it correct?

Thanks