Double Arrow and Double-not Arrow

[jupiterlaw]

In the LRB Ch.6, pg.225, it says in the margins that, "The double-not arrow has no direction. In other words, H could be "first" in the diagram to the left and the meaning would be the same."

The diagram to the left:

G <–|–> H

I am assuming so but wanted to clarify that this would also apply for the Double-arrow?

[Dave Killoran]

Yes, that is correct. Double arrows of any sort don't care about which variable is "first."

[jupiterlaw]

Yes, that is correct. Double arrows of any sort don't care about which variable is "first."

Thanks!