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Proof step 1 from proof size-exgr (conclusion) (back to tree)

# s < # s0 ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s

User applied rule structural induction

And obtained the following new goals

Rule argument

indvar: s

Additional information

Used simplifier rules: gen: ⊦ ;

Proof step 2 from proof size-exgr (previous step) (back to tree)

# ∅ < # s0 ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ ∅

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: Size-empty: ⊦ # ∅ = 0; In-empty: ⊦ ¬ a ∈ ∅; size-zero: ⊦ # s ≠ 0 → s ≠ ∅; size-zero-01: ⊦ s ≠ ∅ → # s ≠ 0; ⊦ 0 < m ↔ m ≠ 0; (s)

Proof step 3 from proof size-exgr (previous step) (back to tree)

# s0 ≠ 0, s0 ≠ ∅ ⊦ ∃ a. a ∈ s0

User applied rule constructor cut

And obtained the following new goals

Rule argument

var: s0

Additional information

Used simplifier rules: gen: ⊦ ;

Proof step 4 from proof size-exgr (previous step) (back to tree)

s0 = s ++ elem, # s0 ≠ 0, s0 ≠ s, s0 ≠ ∅ ⊦ ∃ a. a ∈ s0

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: eq-03: ⊦ s ++ a = s ↔ a ∈ s; ne: ⊦ ∅ ≠ s ++ a; Size-insert: ⊦ ¬ a ∈ s → #(s ++ a) = # s + 1; In-insert: ⊦ a ∈ s ++ b ↔ a = b ∨ a ∈ s; c: ⊦ m + n = n + m; from specification nat-basic a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic ⊦ m + 1 ≠ 0; (s)

Proof step 5 from proof size-exgr (previous step) (back to tree)

¬ elem ∈ s ⊦ ∃ a. a = elem ∨ a ∈ s

Heuristic quantifier closing applied rule exists right

And closed the goal!

Rule argument

pos: right 1 terms: elem

Additional information

Used terms: elem

Proof step 6 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1 ++ elem

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: In-insert: ⊦ a ∈ s ++ b ↔ a = b ∨ a ∈ s; ⊦ m < n → n ≠ 0; (s) f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic

Proof step 7 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic cut applied rule cut formula

And obtained the following new goals

Rule argument

fma: elem ∈ s0

Additional information

Used formulas: elem ∈ s0

Proof step 8 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: ne-01: ⊦ a ∈ s → s ≠ ∅; ne-02: ⊦ a ∈ s → (s = ∅ ↔ false);

Proof step 9 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic weak cut applied rule cut formula

And obtained the following new goals

Rule argument

fma: elem ∈ s1

Additional information

Used formulas: elem ∈ s1

Proof step 10 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, elem ∈ s0, elem ∈ s1, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: eq: ⊦ a ∈ s → s ++ a = s; ne-01: ⊦ a ∈ s → s ≠ ∅; ne-02: ⊦ a ∈ s → (s = ∅ ↔ false);

Proof step 11 from proof size-exgr (previous step) (back to tree)

# s1 < # s0, elem ∈ s0, elem ∈ s1, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 4 terms: s0

Additional information

Used terms: s0

Proof step 12 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, elem ∈ s0, ¬ elem ∈ s1, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: Size-insert: ⊦ ¬ a ∈ s → #(s ++ a) = # s + 1;

Proof step 13 from proof size-exgr (previous step) (back to tree)

# s1 + 1 < # s0, elem ∈ s0, ¬ elem ∈ s1, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

User applied rule constructor cut

And obtained the following new goals

Rule argument

var: s1

Additional information

Used simplifier rules: gen: ⊦ ;

Proof step 14 from proof size-exgr (previous step) (back to tree)

s1 = ∅, # s1 + 1 < # s0, elem ∈ s0, ¬ elem ∈ s1, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: Size-empty: ⊦ # ∅ = 0; In-empty: ⊦ ¬ a ∈ ∅; ⊦ 0 < m ↔ m ≠ 0; (s) ⊦ 1 < m ↔ ¬(m = 0 ∨ m = 1); (s)

Proof step 15 from proof size-exgr (previous step) (back to tree)

# s0 ≠ 1, # s0 ≠ 0, elem ∈ s0, ∀ s. # s ≠ 0 → (∃ elem0. elem0 ∈ s) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: <toplevel>, name:indef, seq: ⊦ a ∈ s ↔ (∃ s0. s = s0 ++ a ∧ ¬ a ∈ s0), subst:[s, a] → [s0, elem], <all paths>

Additional information

Used terms: s0, elem

Proof step 16 from proof size-exgr (previous step) (back to tree)

⊦ a ∈ s ↔ (∃ s0. s = s0 ++ a ∧ ¬ a ∈ s0)

Lemma indef

Proof step 17 from proof size-exgr (previous step) (back to tree)

# s0 ≠ 1, # s0 ≠ 0, ∀ s. # s ≠ 0 → (∃ elem0. elem0 ∈ s), ∃ s1. s0 = s1 ++ elem ∧ ¬ elem ∈ s1 ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: Size-insert: ⊦ ¬ a ∈ s → #(s ++ a) = # s + 1; in-02: ⊦ a ≠ b → (a ∈ s ++ b ↔ a ∈ s); size-zero: ⊦ # s ≠ 0 → s ≠ ∅; size-zero-01: ⊦ s ≠ ∅ → # s ≠ 0; c: ⊦ m + n = n + m; from specification nat-basic a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic ⊦ m + 1 ≠ 0; (s) ⊦ m + n = 1 ↔ m = 0 ∧ n = 1 ∨ n = 0 ∧ m = 1; (ws)

Proof step 18 from proof size-exgr (previous step) (back to tree)

# s1 ≠ 0, s1 ≠ ∅, ¬ elem ∈ s1, ∀ s. # s ≠ 0 → (∃ elem0. elem0 ∈ s) ⊦ ∃ a. a ∈ s1

Heuristic quantifier closing applied rule all left

And obtained the following new goals

Rule argument

pos: left 4 terms: s1

Additional information

Used terms: s1

Proof step 19 from proof size-exgr (previous step) (back to tree)

# s1 ≠ 0, s1 ≠ ∅, ¬ elem ∈ s1, # s1 ≠ 0 → (∃ elem0. elem0 ∈ s1), ∀ s. # s ≠ 0 → (∃ elem0. elem0 ∈ s) ⊦ ∃ a. a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: ne-02: ⊦ a ∈ s → (s = ∅ ↔ false);

Proof step 20 from proof size-exgr (previous step) (back to tree)

# s1 ≠ 0, elem0 ∈ s1, ¬ elem ∈ s1, ∀ s. # s ≠ 0 → (∃ elem0. elem0 ∈ s) ⊦ ∃ a. a ∈ s1

Heuristic quantifier closing applied rule exists right

And closed the goal!

Rule argument

pos: right 1 terms: elem0

Additional information

Used terms: elem0

Proof step 21 from proof size-exgr (previous step) (back to tree)

s1 = s ++ elem0, s1 ≠ s, # s1 + 1 < # s0, elem ∈ s0, ¬ elem ∈ s1, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: eq-03: ⊦ s ++ a = s ↔ a ∈ s; Size-insert: ⊦ ¬ a ∈ s → #(s ++ a) = # s + 1; In-insert: ⊦ a ∈ s ++ b ↔ a = b ∨ a ∈ s;

Proof step 22 from proof size-exgr (previous step) (back to tree)

elem ≠ elem0, (# s + 1) + 1 < # s0, elem ∈ s0, ¬ elem0 ∈ s, ¬ elem ∈ s, ∀ s1. # s + 1 < # s1 → (∃ elem1. elem1 ∈ s1 ∧ elem1 ≠ elem0 ∧ ¬ elem1 ∈ s) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ a ≠ elem0 ∧ ¬ a ∈ s

User applied rule apply rewrite lemma

And obtained the following new goals

Rule argument

spec: <toplevel>, name:indef, seq: ⊦ a ∈ s ↔ (∃ s0. s = s0 ++ a ∧ ¬ a ∈ s0), subst:[s, a] → [s0, elem], <all paths>

Additional information

Used terms: s0, elem

Proof step 23 from proof size-exgr (previous step) (back to tree)

⊦ a ∈ s ↔ (∃ s0. s = s0 ++ a ∧ ¬ a ∈ s0)

Lemma indef

Proof step 24 from proof size-exgr (previous step) (back to tree)

elem ≠ elem0, (# s + 1) + 1 < # s0, ¬ elem0 ∈ s, ¬ elem ∈ s, ∀ s1. # s + 1 < # s1 → (∃ elem1. elem1 ∈ s1 ∧ elem1 ≠ elem0 ∧ ¬ elem1 ∈ s), ∃ s1. s0 = s1 ++ elem ∧ ¬ elem ∈ s1 ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ a ≠ elem0 ∧ ¬ a ∈ s

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: Size-insert: ⊦ ¬ a ∈ s → #(s ++ a) = # s + 1; in-02: ⊦ a ≠ b → (a ∈ s ++ b ↔ a ∈ s); ⊦ m < n → n ≠ 0; (s) f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic c: ⊦ m + n = n + m; from specification nat-basic a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic n0 < n ⊦ m + (* n) < m0 + (* n0) ↔ m + (n - n0) < m0; (s)

Proof step 25 from proof size-exgr (previous step) (back to tree)

elem ≠ elem0, # s + 1 < # s1, ¬ elem ∈ s1, ¬ elem ∈ s, ¬ elem0 ∈ s, ∀ s1. # s + 1 < # s1 → (∃ elem1. elem1 ∈ s1 ∧ elem1 ≠ elem0 ∧ ¬ elem1 ∈ s) ⊦ ∃ a. a ∈ s1 ∧ a ≠ elem0 ∧ ¬ a ∈ s

User applied rule all left

And obtained the following new goals

Rule argument

pos: left 6 terms: s1 abort: F discard: T computed: T

Additional information

Used terms: s1

Proof step 26 from proof size-exgr (previous step) (back to tree)

elem ≠ elem0, # s + 1 < # s1, ¬ elem ∈ s1, ¬ elem ∈ s, ¬ elem0 ∈ s, # s + 1 < # s1 → (∃ elem1. elem1 ∈ s1 ∧ elem1 ≠ elem0 ∧ ¬ elem1 ∈ s) ⊦ ∃ a. a ∈ s1 ∧ a ≠ elem0 ∧ ¬ a ∈ s

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: ne-01: ⊦ a ∈ s → s ≠ ∅; ne-02: ⊦ a ∈ s → (s = ∅ ↔ false);

Proof step 27 from proof size-exgr (previous step) (back to tree)

elem ≠ elem0, elem1 ≠ elem0, # s + 1 < # s1, elem1 ∈ s1, ¬ elem1 ∈ s, ¬ elem0 ∈ s, ¬ elem ∈ s, ¬ elem ∈ s1 ⊦ ∃ a. a ∈ s1 ∧ a ≠ elem0 ∧ ¬ a ∈ s

Heuristic quantifier closing applied rule exists right

And closed the goal!

Rule argument

pos: right 1 terms: elem1

Additional information

Used terms: elem1

Proof step 28 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, ¬ elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ a ≠ elem ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Proof step 29 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, ¬ elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

User applied rule cut formula

And obtained the following new goals

Rule argument

fma: elem ∈ s1

Additional information

Used formulas: elem ∈ s1

Proof step 30 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, elem ∈ s1, ¬ elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: eq: ⊦ a ∈ s → s ++ a = s; ne-01: ⊦ a ∈ s → s ≠ ∅; ne-02: ⊦ a ∈ s → (s = ∅ ↔ false);

Proof step 31 from proof size-exgr (previous step) (back to tree)

# s1 < # s0, elem ∈ s1, ¬ elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

Heuristic quantifier closing applied rule all left

And closed the goal!

Rule argument

pos: left 4 terms: s0

Additional information

Used terms: s0

Proof step 32 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, ¬ elem ∈ s1, ¬ elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

User applied rule all left

And obtained the following new goals

Rule argument

pos: left 4 terms: s1 abort: F discard: F computed: F

Additional information

Used terms: s1

Proof step 33 from proof size-exgr (previous step) (back to tree)

#(s1 ++ elem) < # s0, ¬ elem ∈ s1, ¬ elem ∈ s0, # s1 < # s1 → (∃ a. a ∈ s1 ∧ ¬ a ∈ s1), ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Rule argument

Additional information

Used simplifier rules: Size-insert: ⊦ ¬ a ∈ s → #(s ++ a) = # s + 1; ⊦ ¬ n < n; (s)

Proof step 34 from proof size-exgr (previous step) (back to tree)

# s1 + 1 < # s0, ¬ elem ∈ s1, ¬ elem ∈ s0, ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

Heuristic quantifier closing applied rule all left

And obtained the following new goals

Rule argument

pos: left 4 terms: s0

Additional information

Used terms: s0

Proof step 35 from proof size-exgr (previous step) (back to tree)

# s1 + 1 < # s0, ¬ elem ∈ s1, ¬ elem ∈ s0, # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1), ∀ s0. # s1 < # s0 → (∃ a. a ∈ s0 ∧ ¬ a ∈ s1) ⊦ ∃ a. a ∈ s0 ∧ ¬ a ∈ s1

Heuristic simplifier applied rule simplifier

And closed the goal!

Rule argument

Additional information

Used simplifier rules: c: ⊦ m + n = n + m; from specification nat-basic a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic ⊦ ¬ m < n → ¬ m + m0 < n; (s)

Proof Tree for size-exgr (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