How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
Every finite power of an at most countable set is at most countable
Statement
If is at most countable and , then the finite product is at most countable.
Facts & Assumptions
Given: An at most countable set and a natural number .
The product of two at most countable sets is at most countable (A product of two at most countable sets is at most countable).
A finite set is at most countable, and induction holds on (Finite, countably infinite, countable, uncountable, The principle of mathematical induction).
Proof
For , is a one-point set by [L2], hence at most countable by [L3].
Assume is at most countable.
The product is canonically , so it is at most countable by [L1].
By induction, is at most countable for every .
Depends on
A product of two at most countable sets is at most countable
The principle of mathematical induction
Finite, countably infinite, countable, uncountable
The product set of functions choosing a point in each factor, the projections, the box topology, and the product topology as the initial topology of the projections; the empty product is a one-point space