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Proof step 7 from proof right-trim-app (previous step)

(str0 + str1).last ∈ str ∧ str0 + str1 ≠ "", ∀ char. char ∈ str1 → char ∈ str, ∀ str0, str, str2. # str2 < # str1 → (∀ char. char ∈ str2 → char ∈ str) → string-right-trim(str, str0 + str2) = string-right-trim(str, str0) ⊦ str1 = "", string-right-trim(str, (str0 + str1).butlast) = string-right-trim(str, str0)

User applied rule insert rewrite lemma

And obtained the following new goals

Proof step 8:
⊦ str1 ≠ "" → (str0 + str1).butlast = str0 + str1.butlast
Proof step 9:
str1 ≠ "", (str0 + str1).last ∈ str ∧ str0 + str1 ≠ "", ∀ char. char ∈ str1 → char ∈ str, ∀ str0, str, str2. # str2 < # str1 → (∀ char. char ∈ str2 → char ∈ str) → string-right-trim(str, str0 + str2) = string-right-trim(str, str0) ⊦ str1 = "", string-right-trim(str, str0 + str1.butlast) = string-right-trim(str, str0)

Rule argument

name: butlast-app rotate: F subst: [str1, str0] → [str1, str0]

Additional information

Used terms: str1, str0