X × Y


R ‚" X × Y
(x, y) " R Ð!Ò! xRy


R ‚" X × Y DR = {x " X: "y " Y xRy}

R ‚" X × Y
"R = {y " Y : "x " X xRy}.



c& Ð!Ò! DR = X

c& Ð!Ò! "R = Y

c& Ð!Ò!
"x " X "y1, y2 " Y : xRy1 '" xRy2 =Ò! y1 = y2;

c& Ð!Ò!
"x1, x2 " X "y " Y : x1Ry '" x2Ry =Ò! x1 = x2.























X2 a" X × X R ‚" X2


c& Ð!Ò! "x " X: xRx

c& Ð!Ò! "x, y " X: xRy =Ò! yRx

c& Ð!Ò! "x, y, z " X: xRy '" yRz =Ò! xRz


c& Ð!Ò! "x, y " X: xRy '" yRx =Ò! x = y

c& Ð!Ò! "x, y " X: xRy =Ò! ŹyRx

c& Ð!Ò! "x, y " X: xRy (" yRx (" x = y



R ‚" X2








x R



[x]R = {y " X : yRx}




R ‚" X2























xRy Ð!Ò! x2 + y2 = 1, R ‚" R2.


X Y












R ‚" X × Y X ‚" R, Y ‚" R X Y







xRy Ð!Ò! x2 - y2 = 1

xRy Ð!Ò! 3 + y = log2(x + 1)

xRy Ð!Ò! y = x2 - 4














xRy Ð!Ò! |x| = |y|, X = R

R = {(x, y) " R2: |x| = |y|}

xRy Ð!Ò! x2 d" y2, X = R

xRy Ð!Ò! "k " Z: x - y = 5k, X = R

xRy Ð!Ò! x y X1 = C X2 = N

ARB Ð!Ò! A ‚" B X = P(R)