Definition of the ordered triple (a, b, c) according to Kuratowski's Set Theory. Can someone give Kuratowski's definition of the ordered triple $(a,b,c)$ assuming $A \times B \times C$ is rewritten as $(A \times B) \times C$, please? I noticed there is already an answered question for the ordered $n$-tuple, but (as I'm very new to Maths) I didn't understand it, and I only need the definition for the ordered triple. 

Just track the definition of the ordered pair:
$$\begin{align*}
\langle a,b,c\rangle&=\big\langle\color{blue}{\langle a,b\rangle},c\big\rangle\\
&=\left\langle\color{blue}{\big\{\{a\},\{a,b\}\big\}},c\right\rangle\\
&=\Big\{\left\{\color{blue}{\big\{\{a\},\{a,b\}\big\}}\right\},\left\{\color{blue}{\big\{\{a\},\{a,b\}\big\}},c\right\}\Big\}
\end{align*}$$
(I’ve evaluated it from the inside out; I see now that Henno Brandsma has done it from the outside in. You can take your pick; both work fine.)
