ThmDex – An index of mathematical definitions, results, and conjectures.
Principle of weak mathematical induction
Formulation 2
Let $P = (\mathbb{Z}, {\leq})$ be the D1098: Ordered set of integers such that
(i) $X$ is a D11: Set
(ii) $a \in \mathbb{Z}$ is an D995: Integer
(iii) \begin{equation} [a, \infty) : = \{ n \in \mathbb{Z} : n \geq a \} \end{equation}
(iv) \begin{equation} a \in X \subseteq [a, \infty) \end{equation}
(v) \begin{equation} \forall \, n \in \mathbb{Z} \left( n \in X \quad \implies \quad n + 1 \in X \right) \end{equation}
Then \begin{equation} X = [a, \infty) \end{equation}