In matemat, Grup binon konlet G ko sekät ${\displaystyle \ \cdot :G\times G\to G}$ kel:

• Pro alik ${\displaystyle a,b,c\in G}$, ${\displaystyle a\cdot (b\cdot c)=(a\cdot b)\cdot c}$.
• Dabinon ${\displaystyle e\in G}$, ${\displaystyle e\cdot a=a\cdot e=a}$ pro alik ${\displaystyle a\in G}$. (dilet dientifik)
• Pro alik ${\displaystyle a\in G}$, dabinon ${\displaystyle a^{-1}\in G}$, ${\displaystyle a\cdot a^{-1}=e}$