Description: A member of an upper set of integers is an integer. (Contributed by NM, 6-Sep-2005)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | eluzelz | ⊢ ( 𝑁 ∈ ( ℤ≥ ‘ 𝑀 ) → 𝑁 ∈ ℤ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eluz2 | ⊢ ( 𝑁 ∈ ( ℤ≥ ‘ 𝑀 ) ↔ ( 𝑀 ∈ ℤ ∧ 𝑁 ∈ ℤ ∧ 𝑀 ≤ 𝑁 ) ) | |
| 2 | 1 | simp2bi | ⊢ ( 𝑁 ∈ ( ℤ≥ ‘ 𝑀 ) → 𝑁 ∈ ℤ ) |