Concrete generator style

A style of formal definition that defines a set as a union of a sequence $S_0 \\subseteq S_1 \\subseteq \\dots$ where each $S_{i+1}$ is built from $S_i$ using rules - e.g., for naturals: $S_0 = \\emptyset$

A style of formal definition that defines a set as a union of a sequence $S_0 \subseteq S_1 \subseteq \dots$ where each $S_{i+1}$ is built from $S_i$ using rules - e.g., for naturals: $S_0 = \emptyset$, $S_{i+1} = S_i \cup {0} \cup {succ(n) | n \in S_i}, \mathbb{N} = \bigcup S_i$.