1. Relations binaires 2. Relations d`équivalence 3. Relations d`ordre

RE
E aRb(a, b)∈E×E
≤N Z R
⊂ P(X)X
RE
Rx∈E xRx
Rx, y ∈E xRy⇒yRx
Rx, y ∈E(xRy yRx)⇒x=y
Rx, y, z ∈E(xRy yRz)⇒xRz
E F
f E F E aRb⇔f(a) = f(b)
RE a E
aC(a) = {x∈E, xRa}
RE a, b ∈E aRb a b
RE E
RE E
ER
E/RE→E/Rx E
RE
ER
≤
≤N Z R
E E
x, y ∈E xRy yRx
≤N Z R
N∗
xRy⇒x6=y
<N Z R
(E, ≤)A E
a∈E x ≤a x ≥a x ∈A a
A
a∈A A a
A a = max A a = min A
A
Asup Ainf A