Metamath Proof Explorer


Theorem pfxrn2

Description: The range of a prefix of a word is a subset of the range of that word. Stronger version of pfxrn . (Contributed by Thierry Arnoux, 12-Dec-2023)

Ref Expression
Assertion pfxrn2 ( ( 𝑊 ∈ Word 𝑆𝐿 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ran ( 𝑊 prefix 𝐿 ) ⊆ ran 𝑊 )

Proof

Step Hyp Ref Expression
1 pfxres ( ( 𝑊 ∈ Word 𝑆𝐿 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ( 𝑊 prefix 𝐿 ) = ( 𝑊 ↾ ( 0 ..^ 𝐿 ) ) )
2 1 rneqd ( ( 𝑊 ∈ Word 𝑆𝐿 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ran ( 𝑊 prefix 𝐿 ) = ran ( 𝑊 ↾ ( 0 ..^ 𝐿 ) ) )
3 resss ( 𝑊 ↾ ( 0 ..^ 𝐿 ) ) ⊆ 𝑊
4 3 rnssi ran ( 𝑊 ↾ ( 0 ..^ 𝐿 ) ) ⊆ ran 𝑊
5 2 4 eqsstrdi ( ( 𝑊 ∈ Word 𝑆𝐿 ∈ ( 0 ... ( ♯ ‘ 𝑊 ) ) ) → ran ( 𝑊 prefix 𝐿 ) ⊆ ran 𝑊 )