Question

Scrieti toate submultimile multimilor: B={x;y;z;t}.
VA ROG FRUMOS ,REPEDE!

Answer 1

B={x;y;z;t}
{x} {y} {z} {t} {x,y} {x,z} {x,t} {y,z} {y,t} {z,t} {x,y,z} {x,y,t} {x,z,t} {y,z,t} {x,y,z,t}

Answer 2

O multime cu n elemente are in total $2^n$ submultimi.
In cazul nostru, multimea B va avea $2^4=16$ submultimi.
Submultimile sunt:
1) Multimea vida Ф=1=$C_4^0$
2) {x},{y},{z},{t}=4=$C_4^1$
3) {x,y},{x,z},{x,t},{y,z},{y,t},{z,t}=6=$C_4^2$
4) {x,y,z},{x,y,t},{x,z,t},{y,z,t}=4=$C_4^3$
5) {x,y,z,t}=1=$C_4^4$
1+4+6+4+1=16 submultimi.