Equation 14.81 in Zwiebach: Why No 2?

[ehrenfest]

Homework Statement

In equation 14.81, why are the lower indices of the oscillators alpha^r and alpha^s not divided by 2 like they were in equation 14.77?

Homework Equations

The Attempt at a Solution

 

[nrqed]

Homework Statement

In equation 14.81, why are the lower indices of the oscillators alpha^r and alpha^s not divided by 2 like they were in equation 14.77?

Homework Equations

The Attempt at a Solution

In my edition, equation 14.81 has no alpha (it has integrals with exponentials) . But my equation 14.82 has the commutator of alpha^r and alpha^s and they have, respectively, the subscripts m/2 and n/2.
I am not sure if you have that.

 

[ehrenfest]

I'm sorry. I meant 14.80. Mine has subscripts of m and n (not divided by 2) so it must be a typo. That would make much more sense since the commutator of 14.82 in my book does have subscripts that are divided by 2.

 

[Jimmy Snyder]

I'm pretty sure it's a typo. Here is Professor Zwiebach's errata page. It has his e-mail address where you can send him this one.

http://xserver.lns.mit.edu/~zwiebach/firstcourse.html"