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Proof step 1 from proof diff-union (conclusion) (back to tree)

⊦ (x ∪ y) \ z = (x \ z) ∪ (y \ z)

System applied rule normalize

And obtained the following new goals

Rule argument

Additional information

Proof step 2 from proof diff-union (previous step) (back to tree)

(x ∪ y) \ z ≠ (x \ z) ∪ (y \ z) ⊦

User applied rule structural induction

And obtained the following new goals

Rule argument

indvar: x

Additional information

Used simplifier rules: list('a) freely generated by [], +;;

Proof step 3 from proof diff-union (previous step) (back to tree)

([] ∪ y) \ z ≠ ([] \ z) ∪ (y \ z) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: diff-e: ⊦ [] \ y = []; union: ⊦ x ∪ y = rmdup(x + y); assoc: ⊦ (x ∪ y) ∪ z = x ∪ y ∪ z; a: ⊦ (x + y) + z = x + y + z; from specification polylist ⊦ [] + x = x; (s)

Proof step 4 from proof diff-union (previous step) (back to tree)

rmdup(y) \ z ≠ rmdup(y \ z) ⊦

User applied rule structural induction

And obtained the following new goals

Rule argument

indvar: y

Additional information

Used simplifier rules: diff-e: ⊦ [] \ y = []; list('a) freely generated by [], +;; ⊦ rmdup([]) = []; (s)

Proof step 5 from proof diff-union (previous step) (back to tree)

rmdup(a + y0) \ z ≠ rmdup((a + y0) \ z), ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: ⊦ a + x = a ' + x; (s)

Proof step 6 from proof diff-union (previous step) (back to tree)

rmdup(a ' + y0) \ z ≠ rmdup((a ' + y0) \ z), ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: polylist-dup, name:rm-ifrec, seq: ⊦ rmdup(a ' + x) = (a ∈ x ⊃ rmdup(x);a ' + rmdup(x)), subst:[x, a] → [y0, a], <all paths>

Additional information

Used terms: y0, a

Proof step 7 from proof diff-union (previous step) (back to tree)

⊦ rmdup(a ' + x) = (a ∈ x ⊃ rmdup(x);a ' + rmdup(x))

A spec-lemma

Proof step 8 from proof diff-union (previous step) (back to tree)

(a ∈ y0 ⊃ rmdup(y0);a ' + rmdup(y0)) \ z ≠ rmdup((a ' + y0) \ z), ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

User applied rule case distinction

And obtained the following new goals

Rule argument

pos: left 1

Additional information

Proof step 9 from proof diff-union (previous step) (back to tree)

rmdup(y0) \ z ≠ rmdup((a ' + y0) \ z), a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

User applied rule all left

And obtained the following new goals

Rule argument

pos: left 3 terms: z abort: F discard: T computed: T

Additional information

Used terms: z

Proof step 10 from proof diff-union (previous step) (back to tree)

rmdup(y0) \ z = rmdup(y0 \ z), rmdup(y0) \ z ≠ rmdup((a ' + y0) \ z), a ∈ y0 ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: <toplevel>, name:diff-n, seq: ⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y), subst:[y, x, a] → [z, y0, a], <all paths>

Additional information

Used simplifier rules: diff-y: ⊦ a ∈ y → (a ' + x) \ y = x \ y; a: ⊦ (x + y) + z = x + y + z; from specification polylist Used terms: z, y0, a

Proof step 11 from proof diff-union (previous step) (back to tree)

⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y)

Lemma diff-n

Proof step 12 from proof diff-union (previous step) (back to tree)

rmdup(y0) \ z = rmdup(y0 \ z), rmdup(y0) \ z ≠ rmdup(a + (y0 \ z)), a ∈ y0, ¬ a ∈ z ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: ⊦ a + x = a ' + x; (s)

Proof step 13 from proof diff-union (previous step) (back to tree)

rmdup(y0) \ z = rmdup(y0 \ z), rmdup(y0) \ z ≠ rmdup(a ' + (y0 \ z)), a ∈ y0, ¬ a ∈ z ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: polylist-dup, name:rmdup-n, seq: ⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x), subst:[x, a] → [y0 \ z, a], <all paths>

Additional information

Used simplifier rules: diff-in: ⊦ a ∈ x \ y ↔ a ∈ x ∧ ¬ a ∈ y; ⊦ a + x = a ' + x; (s) ⊦ a ∈ x → rmdup(a ' + x) = rmdup(x); (s) a: ⊦ (x + y) + z = x + y + z; from specification polylist Used terms: y0 \ z, a

Proof step 14 from proof diff-union (previous step) (back to tree)

⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x)

A spec-lemma

Proof step 15 from proof diff-union (previous step) (back to tree)

(a ' + rmdup(y0)) \ z ≠ rmdup((a ' + y0) \ z), ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Proof step 16 from proof diff-union (previous step) (back to tree)

(a ' + rmdup(y0)) \ z ≠ rmdup((a ' + y0) \ z), ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: <toplevel>, name:diff-n, seq: ⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y), subst:[y, x, a] → [z, y0, a], <all paths>

Additional information

Used terms: z, y0, a

Proof step 17 from proof diff-union (previous step) (back to tree)

⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y)

Lemma diff-n

Proof step 18 from proof diff-union (previous step) (back to tree)

(a ' + rmdup(y0)) \ z ≠ rmdup((a ' + y0) \ z), a ∈ z, ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: diff-y: ⊦ a ∈ y → (a ' + x) \ y = x \ y; a: ⊦ (x + y) + z = x + y + z; from specification polylist

Proof step 19 from proof diff-union (previous step) (back to tree)

rmdup(y0) \ z ≠ rmdup(y0 \ z), a ∈ z, ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 4 terms: z

Additional information

Used terms: z

Proof step 20 from proof diff-union (previous step) (back to tree)

(a ' + rmdup(y0)) \ z ≠ rmdup(a + (y0 \ z)), ¬ a ∈ z, ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: diff-n: ⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y); ⊦ a + x = a ' + x; (s) a: ⊦ (x + y) + z = x + y + z; from specification polylist

Proof step 21 from proof diff-union (previous step) (back to tree)

a ' + (rmdup(y0) \ z) ≠ rmdup(a ' + (y0 \ z)), ¬ a ∈ z, ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: polylist-dup, name:rmdup-n, seq: ⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x), subst:[x, a] → [y0 \ z, a], <all paths>

Additional information

Used simplifier rules: diff-in: ⊦ a ∈ x \ y ↔ a ∈ x ∧ ¬ a ∈ y; ⊦ a ∈ x → rmdup(a ' + x) = rmdup(x); (s) a: ⊦ (x + y) + z = x + y + z; from specification polylist Used terms: y0 \ z, a

Proof step 22 from proof diff-union (previous step) (back to tree)

⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x)

A spec-lemma

Proof step 23 from proof diff-union (previous step) (back to tree)

a ' + (rmdup(y0) \ z) ≠ a + rmdup(y0 \ z), ¬ a ∈ y0 \ z, ¬ a ∈ z, ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: diff-in: ⊦ a ∈ x \ y ↔ a ∈ x ∧ ¬ a ∈ y; a: ⊦ (x + y) + z = x + y + z; from specification polylist ⊦ x + y = x + z ↔ y = z; (s) ⊦ a + x = a ' + x; (s)

Proof step 24 from proof diff-union (previous step) (back to tree)

rmdup(y0) \ z ≠ rmdup(y0 \ z), ¬ a ∈ z, ¬ a ∈ y0, ∀ z. rmdup(y0) \ z = rmdup(y0 \ z) ⊦

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 4 terms: z

Additional information

Used terms: z

Proof step 25 from proof diff-union (previous step) (back to tree)

((a + x0) ∪ y) \ z ≠ ((a + x0) \ z) ∪ (y \ z), ∀ y, z. (x0 ∪ y) \ z = (x0 \ z) ∪ (y \ z) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: union: ⊦ x ∪ y = rmdup(x + y); assoc: ⊦ (x ∪ y) ∪ z = x ∪ y ∪ z; ⊦ a + x = a ' + x; (s)

Proof step 26 from proof diff-union (previous step) (back to tree)

rmdup((a ' + x0) + y) \ z ≠ rmdup(((a ' + x0) \ z) + (y \ z)), ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: polylist-dup, name:rm-ifrec, seq: ⊦ rmdup(a ' + x) = (a ∈ x ⊃ rmdup(x);a ' + rmdup(x)), subst:[x, a] → [x0 + y, a], <all paths>

Additional information

Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification polylist Used terms: x0 + y, a

Proof step 27 from proof diff-union (previous step) (back to tree)

⊦ rmdup(a ' + x) = (a ∈ x ⊃ rmdup(x);a ' + rmdup(x))

A spec-lemma

Proof step 28 from proof diff-union (previous step) (back to tree)

(a ∈ x0 + y ⊃ rmdup(x0 + y);a ' + rmdup(x0 + y)) \ z ≠ rmdup(((a ' + x0) \ z) + (y \ z)), ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification polylist ⊦ a ∈ x + y ↔ a ∈ x ∨ a ∈ y; (s)

Proof step 29 from proof diff-union (previous step) (back to tree)

(a ∈ x0 ∨ a ∈ y ⊃ rmdup(x0 + y);a ' + rmdup(x0 + y)) \ z ≠ rmdup(((a ' + x0) \ z) + (y \ z)), ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: <toplevel>, name:diff-n, seq: ⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y), subst:[y, x, a] → [z, x0, a], <all paths>

Additional information

Used terms: z, x0, a

Proof step 30 from proof diff-union (previous step) (back to tree)

⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y)

Lemma diff-n

Proof step 31 from proof diff-union (previous step) (back to tree)

(a ∈ x0 ∨ a ∈ y ⊃ rmdup(x0 + y);a ' + rmdup(x0 + y)) \ z ≠ rmdup(((a ' + x0) \ z) + (y \ z)), a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: diff-y: ⊦ a ∈ y → (a ' + x) \ y = x \ y; a: ⊦ (x + y) + z = x + y + z; from specification polylist

Proof step 32 from proof diff-union (previous step) (back to tree)

(a ∈ x0 ∨ a ∈ y ⊃ rmdup(x0 + y);a ' + rmdup(x0 + y)) \ z ≠ rmdup((x0 \ z) + (y \ z)), a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

User applied rule case distinction

And obtained the following new goals

Rule argument

pos: left 1

Additional information

Proof step 33 from proof diff-union (previous step) (back to tree)

rmdup(x0 + y) \ z ≠ rmdup((x0 \ z) + (y \ z)), a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)), a ∈ x0 ∨ a ∈ y ⊦

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 3 terms: y, z

Additional information

Used terms: y, z

Proof step 34 from proof diff-union (previous step) (back to tree)

(a ' + rmdup(x0 + y)) \ z ≠ rmdup((x0 \ z) + (y \ z)), a ∈ z, ¬ a ∈ y, ¬ a ∈ x0, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 5 terms: y, z

Additional information

Used simplifier rules: diff-y: ⊦ a ∈ y → (a ' + x) \ y = x \ y; a: ⊦ (x + y) + z = x + y + z; from specification polylist Used terms: y, z

Proof step 35 from proof diff-union (previous step) (back to tree)

(a ∈ x0 ∨ a ∈ y ⊃ rmdup(x0 + y);a ' + rmdup(x0 + y)) \ z ≠ rmdup((a + (x0 \ z)) + (y \ z)), ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: ⊦ a + x = a ' + x; (s)

Proof step 36 from proof diff-union (previous step) (back to tree)

(a ∈ x0 ∨ a ∈ y ⊃ rmdup(x0 + y);a ' + rmdup(x0 + y)) \ z ≠ rmdup((a ' + (x0 \ z)) + (y \ z)), ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

User applied rule case distinction

And obtained the following new goals

Rule argument

pos: left 1

Additional information

Proof step 37 from proof diff-union (previous step) (back to tree)

rmdup(x0 + y) \ z ≠ rmdup((a ' + (x0 \ z)) + (y \ z)), ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)), a ∈ x0 ∨ a ∈ y ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Proof step 38 from proof diff-union (previous step) (back to tree)

rmdup(x0 + y) \ z ≠ rmdup((a ' + (x0 \ z)) + (y \ z)), ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)), a ∈ x0 ∨ a ∈ y ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: polylist-dup, name:rmdup-n, seq: ⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x), subst:[x, a] → [(x0 \ z) + (y \ z), a], <all paths>

Additional information

Used simplifier rules: diff-in: ⊦ a ∈ x \ y ↔ a ∈ x ∧ ¬ a ∈ y; ⊦ a + x = a ' + x; (s) ⊦ a ∈ x + y ↔ a ∈ x ∨ a ∈ y; (s) a: ⊦ (x + y) + z = x + y + z; from specification polylist Used terms: (x0 \ z) + (y \ z), a

Proof step 39 from proof diff-union (previous step) (back to tree)

⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x)

A spec-lemma

Proof step 40 from proof diff-union (previous step) (back to tree)

rmdup(x0 + y) \ z ≠ rmdup((a ' + (x0 \ z)) + (y \ z)), a ∈ (x0 \ z) + (y \ z), ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)), a ∈ x0 ∨ a ∈ y ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: a: ⊦ (x + y) + z = x + y + z; from specification polylist ⊦ a ∈ x + y ↔ a ∈ x ∨ a ∈ y; (s) ⊦ a ∈ x → rmdup(a ' + x) = rmdup(x); (s)

Proof step 41 from proof diff-union (previous step) (back to tree)

rmdup(x0 + y) \ z ≠ rmdup((x0 \ z) + (y \ z)), ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)), a ∈ x0 ∨ a ∈ y, a ∈ x0 \ z ∨ a ∈ y \ z ⊦

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 3 terms: y, z

Additional information

Used terms: y, z

Proof step 42 from proof diff-union (previous step) (back to tree)

(a ' + rmdup(x0 + y)) \ z ≠ rmdup((a ' + (x0 \ z)) + (y \ z)), ¬ a ∈ y, ¬ a ∈ x0, ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: diff-n: ⊦ ¬ a ∈ y → (a ' + x) \ y = a + (x \ y); a: ⊦ (x + y) + z = x + y + z; from specification polylist ⊦ a + x = a ' + x; (s)

Proof step 43 from proof diff-union (previous step) (back to tree)

a ' + (rmdup(x0 + y) \ z) ≠ rmdup((a ' + (x0 \ z)) + (y \ z)), ¬ a ∈ y, ¬ a ∈ x0, ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: polylist-dup, name:rmdup-n, seq: ⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x), subst:[x, a] → [(x0 \ z) + (y \ z), a], <all paths>

Additional information

Used simplifier rules: diff-in: ⊦ a ∈ x \ y ↔ a ∈ x ∧ ¬ a ∈ y; ⊦ a ∈ x → rmdup(a ' + x) = rmdup(x); (s) ⊦ a ∈ x + y ↔ a ∈ x ∨ a ∈ y; (s) a: ⊦ (x + y) + z = x + y + z; from specification polylist Used terms: (x0 \ z) + (y \ z), a

Proof step 44 from proof diff-union (previous step) (back to tree)

⊦ ¬ a ∈ x → rmdup(a ' + x) = a + rmdup(x)

A spec-lemma

Proof step 45 from proof diff-union (previous step) (back to tree)

a ' + (rmdup(x0 + y) \ z) ≠ a + rmdup((x0 \ z) + (y \ z)), ¬ a ∈ (x0 \ z) + (y \ z), ¬ a ∈ y, ¬ a ∈ x0, ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: diff-in: ⊦ a ∈ x \ y ↔ a ∈ x ∧ ¬ a ∈ y; a: ⊦ (x + y) + z = x + y + z; from specification polylist ⊦ a ∈ x + y ↔ a ∈ x ∨ a ∈ y; (s) ⊦ x + y = x + z ↔ y = z; (s) ⊦ a + x = a ' + x; (s)

Proof step 46 from proof diff-union (previous step) (back to tree)

rmdup(x0 + y) \ z ≠ rmdup((x0 \ z) + (y \ z)), ¬ a ∈ y, ¬ a ∈ x0, ¬ a ∈ z, ∀ y0, z0. rmdup(x0 + y0) \ z0 = rmdup((x0 \ z0) + (y0 \ z0)) ⊦

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 5 terms: y, z

Additional information

Used terms: y, z

Proof Tree for diff-union (View conclusion)

The following image shows the proof tree of sequent calculus. The proved goal is at the bottom. You can click on the nodes to view additional rules. See here for details on colors in a proof tree.

the proof tree