Description: A metric is a pseudometric. (Contributed by Glauco Siliprandi, 8-Apr-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | metpsmet | ⊢ ( 𝐷 ∈ ( Met ‘ 𝑋 ) → 𝐷 ∈ ( PsMet ‘ 𝑋 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | metxmet | ⊢ ( 𝐷 ∈ ( Met ‘ 𝑋 ) → 𝐷 ∈ ( ∞Met ‘ 𝑋 ) ) | |
| 2 | xmetpsmet | ⊢ ( 𝐷 ∈ ( ∞Met ‘ 𝑋 ) → 𝐷 ∈ ( PsMet ‘ 𝑋 ) ) | |
| 3 | 1 2 | syl | ⊢ ( 𝐷 ∈ ( Met ‘ 𝑋 ) → 𝐷 ∈ ( PsMet ‘ 𝑋 ) ) |