Course notes (chap. 1 Number Theory, chap. 2 ... - McGill University
Course notes (chap. 1 Number Theory, chap. 2 ... - McGill University
Course notes (chap. 1 Number Theory, chap. 2 ... - McGill University
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1 Basic <strong>Number</strong> <strong>Theory</strong><br />
1.1 Definitions<br />
Divisibility:<br />
a|b ⇐⇒ ∃k ∈ Z [b = ak]<br />
Congruences:<br />
a ≡ b (mod n) ⇐⇒ n|(a − b)<br />
Modulo operator: (Maple irem, mod)<br />
b mod n =min{a ≥ 0:a ≡ b<br />
(mod n)}<br />
Division operator: (Maple iquo)<br />
b div n = ⌊b/n⌋ =<br />
b − (b mod n)<br />
n<br />
a ≡ b (mod n) <br />
⟺ <br />
a mod n = b mod n