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Theorem base for Specification set-union

This is a listing of all goals defined over the current specification. Axioms are marked yellow, proved theorems green and unproved theorems blue. Click on individual names to get more information on the proof.

Name: Sequent: Type:
disjoint-02 ⊦ disjoint(s, s0) ∧ a ∈ s → (a ∈ s0 ↔ false) A User Theorem
Delete ⊦ a ∈ s -- a0 ↔ a ≠ a0 ∧ a ∈ s An Axiom
disjoint-01 ⊦ disjoint(s, s0) ∧ a ∈ s0 → (a ∈ s ↔ false) A User Theorem
diff-e ⊦ s \ ∅ = s A User Theorem
diff-int ⊦ (s \ s0) ∩ s0 = ∅ A User Theorem
union-del ⊦ a ∈ (s -- a) ∪ s0 ↔ a ∈ s0 A User Theorem
diff-rc ⊦ (s \ s1) \ s2 = (s \ s2) \ s1 A User Theorem
disjoint-notempty-01 ⊦ disjoint(s, s0) → (disjoint(s, (s0 -- a) ++ a0) ↔ ¬ a0 ∈ s) A User Theorem
selsub-diffs1 ⊆ s2 ⊦ s1 = s2, ∃ s. s ⊆ s2 ∧ s1 = s2 \ s A User Theorem
unsubdel ⊦ s ⊆ s0 ∧ s1 ⊆ s2 ∧ ¬ a ∈ s ∧ ¬ a ∈ s1 → s ∪ s1 ⊆ (s0 -- a) ∪ (s2 -- a) A User Theorem
delsw ⊦ a ≠ a0 → (s ++ a0) -- a = (s -- a) ++ a0 A User Theorem
union-rem-unchdg ⊦ (s0 -- a) ∪ s1 = s0 ∪ s1 ↔ a ∈ s1 ∨ ¬ a ∈ s0 A User Theorem
delete-shift ⊦ a ∈ s → (s -- a = s0 ↔ s = s0 ++ a ∧ ¬ a ∈ s0) A User Theorem
union-sizele-01 ⊦ #((s ∪ s0) ++ a) ≤ # s ↔ s0 ⊆ s ∧ a ∈ s A User Theorem
insdel-sub ⊦ ¬ s -- a ⊆ s0 ∧ a ∈ s → ¬ s ⊆ s0 ++ a A User Theorem
forall-def ⊦ s.forall(p) ↔ (∀ a. a ∈ s → p(a)) A User Theorem
unsubins ⊦ s ++ a ⊆ s ∪ s0 ↔ a ∈ s ∪ s0 A User Theorem
diff-subset-01 ⊦ ((s -- a) ++ a0) \ s0 ⊆ ((s \ s0) -- a) ++ a0 A User Theorem
diff-subset-02 ⊦ s1 ⊆ s2 → s1 \ s ⊆ s2 \ s A User Theorem
int-eq ⊦ s = s ∩ s0 ↔ s ⊆ s0 A User Theorem
disjoint-rec ⊦ disjoint(s, s0 ++ a) ↔ disjoint(s, s0) ∧ ¬ a ∈ s A User Theorem
union-size-insert ⊦ ¬ a ∈ s ∧ ¬ a ∈ s0 → #((s ∪ s0) ++ a) = #(s ∪ s0) + 1 A User Theorem
union-sizele ⊦ #(s ∪ s0) ≤ # s ↔ s0 ⊆ s A User Theorem
union-subset-05 ⊦ s ⊆ s0 → s ∪ s1 ⊆ (s0 ∪ s1) ++ a A User Theorem
del-size-le ⊦ ¬ # s < #(s -- a) A User Theorem
del-in ⊦ ¬ a ∈ s → s -- a = s A User Theorem
union-subset-03 ⊦ s ⊆ s0 ∧ s1 ⊆ s2 ∧ s3 ⊆ s4 → s ∪ s1 ∪ s3 ⊆ s0 ∪ s2 ∪ s4 A User Theorem
union-subset-04 ⊦ s ⊆ s0 ∧ s1 ⊆ s2 ∧ s3 ⊆ s4 → s ∪ s1 ∪ s3 ⊆ (s0 ∪ s2 ∪ s4) ++ a A User Theorem
union-sub ⊦ s0 ⊆ s → s ∪ s0 = s A User Theorem
One ⊦ {a} = ∅ ++ a An Axiom
union-inter-inter-union ⊦ (s0 ∪ s1) ∩ s2 = (s0 ∩ s2) ∪ (s1 ∩ s2) A User Theorem
k-intersect-rec2 ⊦ ¬ a ∈ s ∨ ¬ a ∈ s0 → s ∩ s0 = (s -- a) ∩ (s0 -- a) A User Theorem
diff-add-del-01 ⊦ ¬ a ∈ s1 → s1 \ (s2 ++ a) = s1 \ s2 A User Theorem
del-notin ⊦ s0 = s -- a → ¬ a ∈ s0 A User Theorem
k-union-base ⊦ ∅ ∪ s = s A User Theorem
unsubins-01 ⊦ s ⊆ (s ∪ s0) ++ a A User Theorem
one-in ⊦ a ∈ {a0} ↔ a = a0 A User Theorem
k-intersect-rec1 ⊦ a ∈ s ∧ a ∈ s0 → s ∩ s0 = ((s -- a) ∩ (s0 -- a)) ++ a A User Theorem
del-three ⊦ 2 < # s → #(s -- a -- a0) ≠ 0 A User Theorem
Union ⊦ a ∈ s1 ∪ s2 ↔ a ∈ s1 ∨ a ∈ s2 An Axiom
intdel-empty ⊦ (s -- a) ∩ s0 ≠ ∅ → s ∩ s0 ≠ ∅ A User Theorem
unin-01 ⊦ a ∈ s ∪ s0 ↔ ¬(¬ a ∈ s ∧ ¬ a ∈ s0) A User Theorem
Disjoint ⊦ s1 ∩ s2 = ∅ ↔ disjoint(s1, s2) An Axiom
union-subset-01 ⊦ ¬ s ∪ s1 ⊆ s0 ∪ s1 → ¬ s ⊆ s0 A User Theorem
diff-sub ⊦ s \ s0 ⊆ s A User Theorem
union-subset-02 ⊦ s ⊆ s0 ∧ s1 ⊆ s2 → s ∪ s1 ⊆ (s0 ∪ s2) ++ a A User Theorem
diff-diff-right-union ⊦ s0 \ s1 \ s2 = (s0 \ s1) ∪ (s0 ∩ s2) A User Theorem
sub-rem-inter-rem ⊦ a ∈ s0 → (s \ (s0 -- a)) ∩ (s1 -- a) = (s \ s0) ∩ s1 A User Theorem
intersection-size ⊦ ¬ # s0 + # s < #(s0 ∩ s) A User Theorem
sub-del-05 ⊦ a ≠ a0 ∧ ¬ a ∈ s → s -- a0 ⊆ s -- a0 -- a A User Theorem
filter-union ⊦ (s1 ∪ s2).filter(p) = s1.filter(p) ∪ s2.filter(p) A User Theorem
sub-del-02 ⊦ s -- a ⊆ s A User Theorem
sub-del-01 ⊦ s ⊆ s0 ∧ ¬ a ∈ s → s ⊆ s0 -- a A User Theorem
diff-del ⊦ s = s1 \ s2 ∧ ¬ a ∈ s → (s = (s1 -- a) \ (s2 -- a) ↔ true) A User Theorem
sub-del-04 ⊦ s ⊆ s0 -- a ↔ s ⊆ s0 ∧ ¬ a ∈ s A User Theorem
sub-del-03 ⊦ s ⊆ s0 → s -- a ⊆ s0 A User Theorem
unsubsub ⊦ s ⊆ s0 ∧ s1 ⊆ s2 → s ∪ s1 ⊆ s0 ∪ s2 A User Theorem
del-three-01 ⊦ 2 < # s ∧ a0 ∈ s ∧ a ≠ a0 → #(s -- a -- a0) = #(s -- a) - 1 A User Theorem
union-one ⊦ a ≠ a0 → (a ∈ {a0} ∪ s ↔ a ∈ s) A User Theorem
diff-nin ⊦ s = s1 \ s2 ∧ a ∈ s2 → ¬ a ∈ s A User Theorem
sub-del ⊦ s ⊆ s0 → s -- a ⊆ s0 -- a A User Theorem
undel ⊦ a ∈ s → s ∪ (s0 -- a) = s ∪ s0 A User Theorem
size-rm-less ⊦ #(s -- a) < # s ↔ a ∈ s A User Theorem
del-feq ⊦ s -- a = s0 ++ a0 → a ≠ a0 ∧ a0 ∈ s ∧ ¬ a ∈ s0 A User Theorem
diff-del-02 ⊦ ¬ a ∈ s → s \ s0 ⊆ ((s \ s0) -- a) ++ a0 A User Theorem
diff-del-01 ⊦ ¬ a ∈ s → s \ s0 ⊆ (s \ s0) -- a A User Theorem
disjoint-intersect ⊦ disjoint(s1, s2) → s1 ∩ s2 = ∅ A User Theorem
k-diff-rec2 ⊦ a ∈ s ∧ a ∈ s0 → s \ s0 = (s -- a) \ (s0 -- a) A User Theorem
size-eq ⊦ s0 = s1 → (# s0 = # s1 ↔ true) A User Theorem
del-neq ⊦ s -- a ≠ s0 -- a → s ≠ s0 A User Theorem
k-diff-rec1 ⊦ ¬ a ∈ s ∧ a ∈ s0 → s \ s0 = s \ (s0 -- a) A User Theorem
diff-del-minus-2 ⊦ ¬ a ∈ s1 → (s -- a) \ s1 = (s \ s1) -- a A User Theorem
unadd-01 ⊦ s ∪ (s0 ++ a) = (s ∪ s0) ++ a A User Theorem
Difference ⊦ a ∈ s1 \ s2 ↔ a ∈ s1 ∧ ¬ a ∈ s2 An Axiom
diff-del-minus-3 ⊦ a ∈ s1 → (s -- a) \ s1 = s \ s1 A User Theorem
forall-base ⊦ ∅.forall(p) An Axiom
del-d ⊦ s -- a -- a = s -- a A User Theorem
union-sizeeq ⊦ #(s ∪ s0) = # s ↔ s0 ⊆ s A User Theorem
del-e ⊦ ¬ a ∈ s → ((s ++ a) -- a0 = ∅ ↔ s = ∅ ∧ a = a0) A User Theorem
intersection-insert ⊦ ¬ a ∈ s → s ∩ (s0 ++ a) = s ∩ s0 A User Theorem
union-sub-rem-disjoint ⊦ disjoint(s0, s2) ∧ disjoint(s1, s2) → (s0 ∪ s1 ⊆ s3 \ s2 ↔ s0 ∪ s1 ⊆ s3) A User Theorem
union-size-le ⊦ #(s0 ∪ s1) ≤ # s0 + # s1 A User Theorem
k-delete-rec ⊦ ¬ a0 ∈ s ∧ a ≠ a0 → (s ++ a0) -- a = (s -- a) ++ a0 A User Theorem
size-union ⊦ s ∩ s0 = ∅ → #(s ∪ s0) = # s + # s0 A User Theorem
subset-union-left-rem ⊦ s0 ∪ s1 ⊆ s2 ∪ s1 ↔ s0 ⊆ s2 ∪ s1 A User Theorem
size-eq-ext∀ a. a ∈ s0 ↔ a ∈ s1 ⊦ # s0 = # s1 ↔ true A User Theorem
diff-union ⊦ a ∈ s0 → (a ∈ (s \ s0) ∪ s1 ↔ a ∈ s1) A User Theorem
del-addin-01 ⊦ ¬ a ∈ s → (a ∈ (s -- a0) ++ a1 ↔ a = a1) A User Theorem
union-size ⊦ ¬ #(s ∪ s0) < # s A User Theorem
union-subset ⊦ s ⊆ s0 → s ∪ s1 ⊆ s0 ∪ s1 A User Theorem
disjoint-diff ⊦ disjoint(s, s0) → s \ s0 = s A User Theorem
diff-supset-empty ⊦ s \ (s ∪ s0) = ∅ A User Theorem
disjoint-diff-subset ⊦ disjoint(s0, s1) → (s0 ⊆ s2 \ s1 ↔ s0 ⊆ s2) A User Theorem
diff-one ⊦ (∅ ++ a) \ s ⊆ s0 ++ a A User Theorem
union-difference ⊦ s ⊆ s0 → s ∪ (s0 \ s) = s0 A User Theorem
equal-add-in ⊦ s ++ a = s0 ++ a1 ∧ s0 ++ a1 = (s1 -- a2) ++ a0 ∧ a1 ≠ a0 → a1 ∈ s1 -- a2 A User Theorem
diff-del-plus-1 ⊦ a ∈ s1 → (s ++ a) \ s1 = s \ s1 A User Theorem
size-rm-eq ⊦ #(s -- a) = # s ↔ ¬ a ∈ s A User Theorem
diff-del-plus-2 ⊦ ¬ a ∈ s1 → (s ++ a) \ s1 = (s \ s1) ++ a A User Theorem
union-diff ⊦ ¬ a ∈ s0 ∧ ¬ a ∈ s1 → (a ∈ s \ (s0 ∪ s1) ↔ a ∈ s) A User Theorem
int-idem ⊦ s ∩ s = s A User Theorem
del-addeq ⊦ a ≠ a0 ∧ ¬ a ∈ s ∧ ¬ a ∈ s0 → ((s ++ a) -- a0 = s0 ++ a ↔ s -- a0 = s0) A User Theorem
del-size-01 ⊦ a ∈ s → (# s = n + 1 ↔ #(s -- a) = n) A User Theorem
unall ⊦ s = s0 ∪ s ↔ (∀ a. a ∈ s0 → a ∈ s) A User Theorem
union-diff-union-same ⊦ (s0 ∪ s1) \ (s2 ∪ s1) = s0 \ (s2 ∪ s1) A User Theorem
del-size-02 ⊦ a ∈ s ∧ a ≠ a0 → #(s -- a0 -- a) = #(s -- a0) - 1 A User Theorem
diff-add-del ⊦ s1 \ (s2 ++ a) = (s1 \ s2) -- a A User Theorem
disjoint-all ⊦ disjoint(s, s0) ↔ (∀ a. ¬ a ∈ s ∨ ¬ a ∈ s0) A User Theorem
disjoint-rec2 ⊦ disjoint(s0 ++ a, s) ↔ disjoint(s0, s) ∧ ¬ a ∈ s A User Theorem
uninsubdel ⊦ ¬ a ∈ s ∪ s0 ∧ s1 ⊆ s → ¬ a ∈ (s1 -- a0) ∪ s0 A User Theorem
uninsert ⊦ a ∈ s → (s ∪ s0) ++ a = s ∪ s0 A User Theorem
subseteq-disjoint-empty-right ⊦ s0 ⊆ s1 ∧ disjoint(s2, s1) → disjoint(s2, s0) A User Theorem
subseteq-rem-del ⊦ a ∈ s0 ∧ s0 ⊆ s1 → s1 \ (s0 -- a) = (s1 \ s0) ++ a A User Theorem
add-inter-rem ⊦ ((s0 ++ a) ∩ s1) -- a = (s0 ∩ s1) -- a A User Theorem
del-ne ⊦ 1 < # s → s -- a ≠ ∅ A User Theorem
subset-disjoint-union ⊦ s ⊆ s0 ↔ (∃ s1. s ∪ s1 = s0 ∧ disjoint(s, s1)) A User Theorem
del-feq-01 ⊦ (s ++ a) -- a0 = s0 ++ a1 ∧ ¬ a1 ∈ s → a = a1 ∧ a0 ≠ a1 A User Theorem
del-feq-02 ⊦ (s ++ a) -- a0 = s0 ++ a1 ∧ a ≠ a0 ∧ ¬ a ∈ s0 → a = a1 A User Theorem
una ⊦ (s ∪ s0) ∪ s1 = s ∪ s0 ∪ s1 A User Theorem
unc ⊦ s ∪ s0 = s0 ∪ s A User Theorem
filter-in ⊦ a ∈ s.filter(p) ↔ a ∈ s ∧ p(a) An Axiom
une ⊦ s ∪ ∅ = s A User Theorem
size-del-leq ⊦ # s ≤ #(s -- a) ↔ ¬ a ∈ s A User Theorem
diff-sub-sizes = s0 \ s1, s1 ⊆ s0 ⊦ # s = # s0 - # s1 A User Theorem
unidem ⊦ s ∪ s = s A User Theorem
add-rem-sub ⊦ (s0 ++ a) \ (s1 -- a) = (s0 \ s1) ++ a A User Theorem
del-addeq-06 ⊦ (s ++ a ++ a0) -- a = (s ++ a0) -- a A User Theorem
subseteq-disjoint-empty ⊦ s0 ⊆ s1 ∧ disjoint(s1, s2) → disjoint(s0, s2) A User Theorem
del-addeq-01 ⊦ (s ++ a) -- a0 -- a = s -- a0 -- a A User Theorem
union-size-02 ⊦ ¬ a ∈ s ∧ a ∈ s0 → #(s ∪ s0) = #(s ∪ (s0 -- a)) + 1 A User Theorem
union-size-03 ⊦ #(s0 ∪ s1) = # s0 + # s1 - #(s0 ∩ s1) A User Theorem
del-addeq-05 ⊦ (s ++ a) -- a = s -- a A User Theorem
del-addeq-04 ⊦ ¬ a ∈ s → (s ++ a) -- a = s A User Theorem
del-addeq-03 ⊦ a ∈ s ∧ a ≠ a0 → (s -- a0) ++ a = s -- a0 A User Theorem
del-addeq-02 ⊦ a ∈ s → (s -- a) ++ a = s A User Theorem
del-in-01 ⊦ a ≠ a0 → (a ∈ s -- a0 ↔ a ∈ s) A User Theorem
k-intersect-base ⊦ ∅ ∩ s = ∅ A User Theorem
union-size-01 ⊦ ¬ a ∈ s → ¬ #((s ∪ s0) ++ a) ≤ # s A User Theorem
sub-ade ⊦ s ⊆ s0 → (s -- a) ++ a0 ⊆ (s0 -- a) ++ a0 A User Theorem
sub-ade-01 ⊦ s ⊆ s0 → (s -- a) ++ a0 ++ a1 ⊆ (s0 -- a) ++ a0 ++ a1 A User Theorem
del-in-03 ⊦ s -- a = s ↔ ¬ a ∈ s A User Theorem
sub-ade-03 ⊦ s ⊆ s0 ∧ ¬ a ∈ s → s ⊆ (s0 -- a) ++ a0 ++ a1 A User Theorem
del-in-02 ⊦ ¬ a ∈ s -- a A User Theorem
sub-ade-02 ⊦ s ⊆ s0 ∧ ¬ a ∈ s → s ⊆ (s0 -- a) ++ a0 A User Theorem
disjoint-diff1 ⊦ disjoint(s0 \ s1, s1) A User Theorem
unindel ⊦ ¬ a ∈ s ∪ s0 → ¬ a ∈ (s -- a0) ∪ s0 A User Theorem
disjoint-diff2 ⊦ disjoint(s1, s0 \ s1) A User Theorem
exists-def ⊦ s.exists(p) ↔ (∃ a. a ∈ s ∧ p(a)) A User Theorem
diff-subset ⊦ s \ (s0 ∪ s1) ⊆ s \ s1 A User Theorem
disjointu-empty ⊦ disjoint(s, s0 ∪ s1) ↔ disjoint(s, s0) ∧ disjoint(s, s1) A User Theorem
del-d-01 ⊦ s -- a -- a0 -- a = s -- a0 -- a A User Theorem
intexins ∩ s0 ≠ ∅ ⊦ ∃ a. a ∈ s ∧ a ∈ s0 A User Theorem
uneq ⊦ s ∪ s0 = s0 ↔ s ⊆ s0 A User Theorem
union-sub-01 ⊦ s0 ⊆ s → s0 ∪ s = s A User Theorem
sub-union ⊦ s ⊆ s0 → s ⊆ s0 ∪ s1 A User Theorem
diff-int-01 ⊦ (s \ (s0 ∪ s1)) ∩ s0 = ∅ A User Theorem
union-rem-add ⊦ a ∈ s0 → ((s0 -- a) ∪ s1) ++ a = s0 ∪ s1 A User Theorem
diff-union-01 ⊦ ¬ a ∈ s → (a ∈ (s \ s0) ∪ s1 ↔ a ∈ s1) A User Theorem
map-base ⊦ ∅.map(f) = ∅ An Axiom
delsw-02 ⊦ s -- a0 -- a = s -- a -- a0 ↔ true A User Theorem
diff-empty ⊦ s1 \ s2 = ∅ ∧ a ∈ s1 → a ∈ s2 A User Theorem
one-min ⊦ s = ∅ ++ a → s -- a = ∅ A User Theorem
del-size ⊦ a ∈ s → #(s -- a) = # s - 1 A User Theorem
del-addin ⊦ ¬ a ∈ s → (a ∈ (s -- a0) ++ a1 ++ a2 ↔ a = a1 ∨ a = a2) A User Theorem
int-del-rew ⊦ s ∩ (s0 -- a) = (s ∩ s0) -- a A User Theorem
diff-idem ⊦ s \ s = ∅ A User Theorem
unin ⊦ ¬ a ∈ s → (a ∈ s ∪ s0 ↔ a ∈ s0) A User Theorem
diff-diff-right ⊦ a ∈ s2 → (a ∈ s0 \ s1 \ s2 ↔ a ∈ s0) A User Theorem
diff-union-04 ⊦ s ∪ (s0 \ s) = s ∪ s0 A User Theorem
diff-union-03 ⊦ (s ∪ s0) \ s1 = (s \ s1) ∪ (s0 \ s1) A User Theorem
diff-union-02 ⊦ ¬ a ∈ s → (a ∈ ((s ∪ s2) \ s0) ∪ s1 ↔ a ∈ (s2 \ s0) ∪ s1) A User Theorem
union-size-not-less-02 ⊦ # s0 ≤ m ∧ # s1 ≤ n → ¬ m + n + 1 < #(s0 ∪ s1) A User Theorem
map-rec ⊦ ¬ a ∈ s → (s ++ a).map(f) = s.map(f) ++ f(a) An Axiom
union-size-not-less-01 ⊦ # s0 ≤ m ∧ # s1 ≤ n → ¬ m + n < #(s0 ∪ s1) A User Theorem
del-e-02 ⊦ s -- a = ∅ ↔ s = ∅ ∨ s = ∅ ++ a A User Theorem
del-e-01 ⊦ ∅ -- a = ∅ A User Theorem
subset-del ⊦ s ⊆ s -- a ↔ ¬ a ∈ s A User Theorem
disjoint-empty2 ⊦ disjoint(∅, s) A User Theorem
une-01 ⊦ s1 ∪ s2 = ∅ ↔ s1 = ∅ ∧ s2 = ∅ A User Theorem
delete-subset ⊦ (s -- a) ++ a0 ⊆ s ++ a0 A User Theorem
sub-union-03 ⊦ s ++ a ⊆ (s ∪ s0) ++ a A User Theorem
sub-union-04 ⊦ s ++ a ⊆ (s ∪ s0) ++ a0 ++ a A User Theorem
sub-union-01 ⊦ s ⊆ s0 → s ⊆ (s0 ∪ s1) ++ a A User Theorem
delete-insert ⊦ (s -- a) ++ a = s ++ a A User Theorem
sub-union-02 ⊦ s ⊆ (s ∪ s0) ++ a ++ a0 A User Theorem
int-inserte ⊦ a ∈ s → s ∩ (s0 ++ a) ≠ ∅ A User Theorem
sub-union-05 ⊦ s ⊆ (s ∪ s0) ++ a ++ a0 ++ a1 A User Theorem
union-size-ls-in ⊦ a ∈ s0 ∧ a ∈ s1 → #(s0 ∪ s1) < # s0 + # s1 A User Theorem
k-union-rec2 ⊦ ¬ a ∈ s ∧ ¬ a ∈ s0 → (s ++ a) ∪ s0 = (s ∪ s0) ++ a A User Theorem
k-union-rec1 ⊦ ¬ a ∈ s ∧ a ∈ s0 → (s ++ a) ∪ s0 = s ∪ s0 A User Theorem
delsw-01 ⊦ s -- a0 -- a = s -- a -- a0 A User Theorem
del-neq-02 ⊦ s -- a ≠ s0 ++ a A User Theorem
union-size-not-less ⊦ ¬ # s0 + # s1 < #(s0 ∪ s1) A User Theorem
del-neq-01 ⊦ a ≠ a0 → (s ++ a) -- a0 ≠ ∅ A User Theorem
unsubdel-01 ⊦ s ⊆ s0 ∧ ¬ a ∈ s → (s0 -- a) ∪ s = s0 -- a A User Theorem
filter-add ⊦ (s ++ a).filter(p) = (p(a) ⊃ s.filter(p) ++ a;s.filter(p)) A User Theorem
Intersect ⊦ a ∈ s1 ∩ s2 ↔ a ∈ s1 ∧ a ∈ s2 An Axiom
disjoint-empty ⊦ disjoint(s, ∅) A User Theorem
unsub ⊦ s ⊆ s ∪ s0 A User Theorem
disjointu-empty2 ⊦ disjoint(s0 ∪ s1, s) ↔ disjoint(s0, s) ∧ disjoint(s1, s) A User Theorem
exists-rec ⊦ (s ++ a).exists(p) ↔ p(a) ∨ s.exists(p) An Axiom
delsw-suc ⊦ a ≠ a0 → ((s ++ a0) -- a = (s -- a) ++ a0 ↔ true) A User Theorem
unsub-union-01 ⊦ s1 ∪ s2 ⊆ s ↔ s1 ⊆ s ∧ s2 ⊆ s A User Theorem
int-inse ⊦ s ∩ (s0 ++ a) = ∅ → s ∩ s0 = ∅ ∧ ¬ a ∈ s A User Theorem
subsub-del ⊦ s -- a ⊆ s0 ∧ ¬ s ⊆ s0 ∧ a ∈ s → ¬ a ∈ s0 A User Theorem
diff-del-minus ⊦ (s -- a) \ (s1 -- a) = (s -- a) \ s1 A User Theorem
diff-e-01 ⊦ ∅ \ s = ∅ A User Theorem
exists-base ⊦ ¬ ∅.exists(p) An Axiom
forall-rec ⊦ (s ++ a).forall(p) ↔ p(a) ∧ s.forall(p) An Axiom
rem-union-ins ⊦ (s0 ∪ (s1 -- a)) ++ a = (s0 ∪ s1) ++ a A User Theorem
rem-disjoint ⊦ disjoint(s \ s0, s1) ∧ (s2 \ s) ∩ s1 = ∅ → (s2 \ s0) ∩ s1 = ∅ A User Theorem
filter-empty ⊦ ∅.filter(p) = ∅ A User Theorem
union-rewone ⊦ s ++ a = s ∪ {a} A User Theorem
del-eq ⊦ a ∈ s ∧ a ∈ s0 → (s -- a = s0 -- a ↔ s = s0) A User Theorem
unadd ⊦ (s ++ a) ∪ s0 = (s ∪ s0) ++ a A User Theorem
disjoint-rem ⊦ disjoint(s0, s1) → (s0 -- a) ∩ s1 = ∅ A User Theorem
del-twos -- a -- a0 = ∅ ⊦ s = ∅ ∨ s = ∅ ++ a ∨ s = ∅ ++ a0 ∨ s = ∅ ++ a ++ a0 A User Theorem
undel-05 ⊦ ¬ a ∈ s ∧ ¬ a ∈ s0 → (s -- a) ∪ (s0 -- a) = s ∪ s0 A User Theorem
intersect-add-rem ⊦ (s0 ++ a) ∩ (s1 -- a) = (s0 ∩ s1) -- a A User Theorem
undel-06 ⊦ (s -- a -- a0) ∪ s0 = (s -- a0 -- a) ∪ s0 ↔ true A User Theorem
undel-01 ⊦ (s ∪ s0) -- a = s ∪ (s0 -- a) ↔ ¬ a ∈ s A User Theorem
undel-02 ⊦ (s ∪ s0) -- a = (s -- a) ∪ (s0 -- a) A User Theorem
undel-03 ⊦ ¬ a ∈ s → s ∪ (s0 -- a) = (s ∪ s0) -- a A User Theorem
undel-04 ⊦ (s -- a) ∪ (s0 -- a) = (s ∪ s0) -- a A User Theorem
intersection-shift ⊦ a ∈ s → s ∩ (s0 ++ a) = (s ∩ s0) ++ a A User Theorem
del-del-one ⊦ a ≠ a0 → (∅ ++ a) -- a0 = ∅ ++ a A User Theorem
disjoint-sym ⊦ disjoint(s, s0) → (disjoint(s0, s) ↔ true) A User Theorem
int-subs01 ⊦ s ∩ s0 ⊆ s A User Theorem
int-a ⊦ (s ∩ s0) ∩ s1 = s ∩ s0 ∩ s1 A User Theorem
int-e ⊦ s ∩ ∅ = ∅ A User Theorem
int-c ⊦ s ∩ s0 = s0 ∩ s A User Theorem