[Imprint][Data Privacy Statement][E-Mail]

View long theorem info. View the proof. Back to main index. View the specification. View theorem base summary, View theorem base listing, the used properties by spec, the dependency list, the symbol table,

Proof step 2 from proof firstN-lastN-in (previous step)

n ≤ # x, a ∈ x ⊦ a ∈ lastn(n, x), a ∈ firstn(# x - n, x)

User applied rule insert lemma

And obtained the following new goals

Proof step 3:
⊦ n ≤ # x → firstn(# x - n, x) + lastn(n, x) = x
Proof step 4:
n ≤ # x → firstn(# x - n, x) + lastn(n, x) = x, n ≤ # x, a ∈ x ⊦ a ∈ lastn(n, x), a ∈ firstn(# x - n, x)

Rule argument

spec: list-del inst: name: firstN-lastN seq: ⊦ n ≤ # x → firstn(# x - n, x) + lastn(n, x) = x subst: [n, x] → [n, x] flags: current, []

Additional information

Used terms: n, x