[tex]\it \subset\ este\ semnul\ inclus\\ \\ \{1,\ 2,\ 3\}\ \subset\ \{0,\ 1,\ 2,\ 3,\ 4\}\\ \\ \rule{94}{0.3}\\ \\ \supset\ este\ semnul \ includ e\\ \\ \{2,\ 4,\ 6,\ 8\}\ \supset\ \{2,\ 8\}\\ \\ \rule{100}{0,3}\\ \\ \cap\ este\ semnul\ intersectat\\ \\ \cup\ este\ semnul\ reunit[/tex]
[tex]\ie\mathbb{Z}^ {*} =\mathbb{Z}\setminus\{0\}[/tex]
