Miscellany

Multimi: multimea = o colectie de obiecte distincte
Multimea vida : nu are nici un element.
Egalitatea : A=B x    A  x  B
Proprietati :
-reflexivitatea A, A  A
-simetria A  B  B  A
-tranzitivitatea A  B B  C  A  C
Incluziunea : A  B  x  A  x  B
Proprietati :
-reflexivitatea A, A  A
-antisimetria A  B B  A A  B
-tranzitivitatea A  B B  C  A  C
-neincluziunea A   A A  B
Multimi de numere : N Z Q R   
Naturale =N N=0,1,2,3.n 
Intregi = Z Z=-n., 33,..  7,.. 1,0,1..5,..11,..24,n 
Rationale = Q Q a ;a,b Z,b 0
b
    
 
; pozitive a 0
b
 ;negative a 0
b
 ; 5 ..... 7
3 2
Irationale = R Q ex: 13,  5,
Reale = R R  N  Z Q (R Q)