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.
The number is irrational
Statement
The number is irrational.
Facts & Assumptions
Given: The series definition of (The real exponential function and the number by a power series).
Factorials are nonzero naturals and obey their recurrence. If , then , so divides (The factorial and the falling factorial , defined by recursion in , for ; hence , the quotient is a natural number, and ). Every positive natural has a positive, hence nonzero, canonical real image, and the canonical map preserves products (The canonical natural of a field, Canonical naturals are positive and strictly increasing).
The exponential factorial tail is bounded by A geometric bound for tails of the exponential series.
Every rational has an integer representative with positive denominator; every positive integer is the image of a unique natural . The embeddings are injective, preserve arithmetic and order, and the integers are closed under finite sums and differences (Every rational has a positive-denominator representative, The naturals embed in the integers, The integers embed in the rationals, The unique embedding of ℚ into an ordered field, The integers form a commutative ring).
Proof
Assume . By [L3], write in with and , , using the canonical embeddings. Choose a natural (Every complete ordered field is Archimedean).
Put . Every tail term is positive, so . Applying [L2] with and , then using the factorial recurrence, gives because .
The number from step 2.1 is an embedded integer. Indeed, for each , [L1] gives a natural with . Also for the natural with , and [L1] at gives ; hence for some natural . By [L3] and multiplicativity of the embeddings, where is the real image of the integer . Therefore is a difference of embedded integers and is itself an embedded integer.
Since the embedding preserves order, no embedded integer lies strictly between and , contradicting steps 3.1 and 2.1. Therefore .
Depends on
- A geometric bound for tails of the exponential series
- The real exponential function and the number $e$ by a power series
- The rationals as equivalence classes of pairs of integers
- The integers as equivalence classes of pairs of naturals
- The factorial $n!$ and the falling factorial $n^{\underline{k}}$, defined by recursion in $\mathbb{N}$
- Every complete ordered field is Archimedean
- The canonical natural $\iota(n) = n \cdot 1_F$ of a field
- Canonical naturals are positive and strictly increasing
- Every rational has a positive-denominator representative
- The naturals embed in the integers
- The integers embed in the rationals
- The unique embedding of ℚ into an ordered field
- $\binom{n}{k}\,k!\,(n-k)! = n!$ for $k \le n$; hence $\binom{n}{k}\,k! = n^{\underline{k}}$, the quotient $n!/(k!(n-k)!)$ is a natural number, and $\binom{n}{k} = \binom{n}{n-k}$
- The integers form a commutative ring
Used by
Dependency tree · next 3 levels
Direct dependencies and their dependencies through the next three levels: 108 results over 28 levels. An arrow runs from a result to what uses it, and this result sits at the bottom with a heavier outline. Click the chart to enlarge it.
Sources
- MIT OpenCourseWare 18.100B Real Analysis, Spring 2025 full lecture notes (standard reference, not scraped)
- J. Lebl, Basic Analysis, Analytic Functions (standard reference, not scraped)
- MIT Proofs in Analysis and Probability, Lecture 2 notes (standard reference, not scraped)
- LSU MATH 7230, Homework 1 (standard reference, not scraped)