Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I was reading the following paper and I am stuck at the second last step. Can you please explain the L multiplied by (mod 19) step (right after (6)) enter image description here

How are they getting (3/5)mod 19 =12 ? similarly how are they getting the other matrix elements 16, 3, 12 ?

share|cite|improve this question
up vote 1 down vote accepted

The multiplicative inverse of 5 is 4 mod 19 like how the paper says. So instead of dividing by 5, you can just multiply by 4 and then reduce modulo 19 if the result is too large.



-4*4=-16=3 (mod 19)

share|cite|improve this answer
ok got it. thanks. – Wildling Feb 20 '13 at 15:05

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.