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I’m reading "An Introduction to Mathematical Cryptography" by J.Hoffstein. I’m stuck with the task on NTRUMLS(blue rectangle):

I was wondering if there was a mistake in the assignment. The maximum answer I can come up with is q/2 + p**2 * N / 2( because sp + p * r part gives us q/2 and a * f gives us maximum (p * p/2) * N (when all the +-p and +-p/2 match).

Further, I’ve checked his another publication:
TRANSCRIPT SECURE SIGNATURES BASED ON
MODULAR LATTICES

Well, I was not be able to find any information about why he sets Bs = Bt = B = ceil(p**2 * N / 4) there.

I hope you can help me figure this out.