Theorem List for New Foundations Explorer - 3301-3400 *Has distinct variable
group(s)
Type | Label | Description |
Statement |
|
Theorem | eqsstri 3301 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 16-Jul-1995.)
|
⊢ A =
B
& ⊢ B ⊆ C ⇒ ⊢ A ⊆ C |
|
Theorem | eqsstr3i 3302 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 19-Oct-1999.)
|
⊢ B =
A
& ⊢ B ⊆ C ⇒ ⊢ A ⊆ C |
|
Theorem | sseqtri 3303 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 28-Jul-1995.)
|
⊢ A ⊆ B
& ⊢ B =
C ⇒ ⊢ A ⊆ C |
|
Theorem | sseqtr4i 3304 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 4-Apr-1995.)
|
⊢ A ⊆ B
& ⊢ C =
B ⇒ ⊢ A ⊆ C |
|
Theorem | eqsstrd 3305 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 25-Apr-2004.)
|
⊢ (φ
→ A = B)
& ⊢ (φ
→ B ⊆ C) ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | eqsstr3d 3306 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 25-Apr-2004.)
|
⊢ (φ
→ B = A)
& ⊢ (φ
→ B ⊆ C) ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | sseqtrd 3307 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 25-Apr-2004.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ (φ
→ B = C) ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | sseqtr4d 3308 |
Substitution of equality into a subclass relationship. (Contributed by
NM, 25-Apr-2004.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ (φ
→ C = B) ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | 3sstr3i 3309 |
Substitution of equality in both sides of a subclass relationship.
(Contributed by NM, 13-Jan-1996.) (Proof shortened by Eric Schmidt,
26-Jan-2007.)
|
⊢ A ⊆ B
& ⊢ A =
C
& ⊢ B =
D ⇒ ⊢ C ⊆ D |
|
Theorem | 3sstr4i 3310 |
Substitution of equality in both sides of a subclass relationship.
(Contributed by NM, 13-Jan-1996.) (Proof shortened by Eric Schmidt,
26-Jan-2007.)
|
⊢ A ⊆ B
& ⊢ C =
A
& ⊢ D =
B ⇒ ⊢ C ⊆ D |
|
Theorem | 3sstr3g 3311 |
Substitution of equality into both sides of a subclass relationship.
(Contributed by NM, 1-Oct-2000.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ A =
C
& ⊢ B =
D ⇒ ⊢ (φ
→ C ⊆ D) |
|
Theorem | 3sstr4g 3312 |
Substitution of equality into both sides of a subclass relationship.
(Contributed by NM, 16-Aug-1994.) (Proof shortened by Eric Schmidt,
26-Jan-2007.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ C =
A
& ⊢ D =
B ⇒ ⊢ (φ
→ C ⊆ D) |
|
Theorem | 3sstr3d 3313 |
Substitution of equality into both sides of a subclass relationship.
(Contributed by NM, 1-Oct-2000.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ (φ
→ A = C)
& ⊢ (φ
→ B = D) ⇒ ⊢ (φ
→ C ⊆ D) |
|
Theorem | 3sstr4d 3314 |
Substitution of equality into both sides of a subclass relationship.
(Contributed by NM, 30-Nov-1995.) (Proof shortened by Eric Schmidt,
26-Jan-2007.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ (φ
→ C = A)
& ⊢ (φ
→ D = B) ⇒ ⊢ (φ
→ C ⊆ D) |
|
Theorem | syl5eqss 3315 |
B chained subclass and equality deduction. (Contributed by NM,
25-Apr-2004.)
|
⊢ A =
B
& ⊢ (φ
→ B ⊆ C) ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | syl5eqssr 3316 |
B chained subclass and equality deduction. (Contributed by NM,
25-Apr-2004.)
|
⊢ B =
A
& ⊢ (φ
→ B ⊆ C) ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | syl6sseq 3317 |
A chained subclass and equality deduction. (Contributed by NM,
25-Apr-2004.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ B =
C ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | syl6sseqr 3318 |
A chained subclass and equality deduction. (Contributed by NM,
25-Apr-2004.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ C =
B ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | syl5sseq 3319 |
Subclass transitivity deduction. (Contributed by Jonathan Ben-Naim,
3-Jun-2011.)
|
⊢ B ⊆ A
& ⊢ (φ
→ A = C) ⇒ ⊢ (φ
→ B ⊆ C) |
|
Theorem | syl5sseqr 3320 |
Subclass transitivity deduction. (Contributed by Jonathan Ben-Naim,
3-Jun-2011.)
|
⊢ B ⊆ A
& ⊢ (φ
→ C = A) ⇒ ⊢ (φ
→ B ⊆ C) |
|
Theorem | syl6eqss 3321 |
A chained subclass and equality deduction. (Contributed by Mario
Carneiro, 2-Jan-2017.)
|
⊢ (φ
→ A = B)
& ⊢ B ⊆ C ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | syl6eqssr 3322 |
A chained subclass and equality deduction. (Contributed by Mario
Carneiro, 2-Jan-2017.)
|
⊢ (φ
→ B = A)
& ⊢ B ⊆ C ⇒ ⊢ (φ
→ A ⊆ C) |
|
Theorem | eqimss 3323 |
Equality implies the subclass relation. (Contributed by NM, 5-Aug-1993.)
(Proof shortened by Andrew Salmon, 21-Jun-2011.)
|
⊢ (A =
B → A ⊆ B) |
|
Theorem | eqimss2 3324 |
Equality implies the subclass relation. (Contributed by NM,
23-Nov-2003.)
|
⊢ (B =
A → A ⊆ B) |
|
Theorem | eqimssi 3325 |
Infer subclass relationship from equality. (Contributed by NM,
6-Jan-2007.)
|
⊢ A =
B ⇒ ⊢ A ⊆ B |
|
Theorem | eqimss2i 3326 |
Infer subclass relationship from equality. (Contributed by NM,
7-Jan-2007.)
|
⊢ A =
B ⇒ ⊢ B ⊆ A |
|
Theorem | nssne1 3327 |
Two classes are different if they don't include the same class.
(Contributed by NM, 23-Apr-2015.)
|
⊢ ((A ⊆ B ∧ ¬ A ⊆ C) →
B ≠ C) |
|
Theorem | nssne2 3328 |
Two classes are different if they are not subclasses of the same class.
(Contributed by NM, 23-Apr-2015.)
|
⊢ ((A ⊆ C ∧ ¬ B ⊆ C) →
A ≠ B) |
|
Theorem | nss 3329* |
Negation of subclass relationship. Exercise 13 of [TakeutiZaring]
p. 18. (Contributed by NM, 25-Feb-1996.) (Proof shortened by Andrew
Salmon, 21-Jun-2011.)
|
⊢ (¬ A
⊆ B
↔ ∃x(x ∈ A ∧ ¬ x ∈ B)) |
|
Theorem | ssralv 3330* |
Quantification restricted to a subclass. (Contributed by NM,
11-Mar-2006.)
|
⊢ (A ⊆ B →
(∀x
∈ B
φ → ∀x ∈ A φ)) |
|
Theorem | ssrexv 3331* |
Existential quantification restricted to a subclass. (Contributed by
NM, 11-Jan-2007.)
|
⊢ (A ⊆ B →
(∃x
∈ A
φ → ∃x ∈ B φ)) |
|
Theorem | ralss 3332* |
Restricted universal quantification on a subset in terms of superset.
(Contributed by Stefan O'Rear, 3-Apr-2015.)
|
⊢ (A ⊆ B →
(∀x
∈ A
φ ↔ ∀x ∈ B (x ∈ A → φ))) |
|
Theorem | rexss 3333* |
Restricted existential quantification on a subset in terms of superset.
(Contributed by Stefan O'Rear, 3-Apr-2015.)
|
⊢ (A ⊆ B →
(∃x
∈ A
φ ↔ ∃x ∈ B (x ∈ A ∧ φ))) |
|
Theorem | ss2ab 3334 |
Class abstractions in a subclass relationship. (Contributed by NM,
3-Jul-1994.)
|
⊢ ({x ∣ φ}
⊆ {x
∣ ψ} ↔ ∀x(φ → ψ)) |
|
Theorem | abss 3335* |
Class abstraction in a subclass relationship. (Contributed by NM,
16-Aug-2006.)
|
⊢ ({x ∣ φ}
⊆ A
↔ ∀x(φ →
x ∈
A)) |
|
Theorem | ssab 3336* |
Subclass of a class abstraction. (Contributed by NM, 16-Aug-2006.)
|
⊢ (A ⊆ {x ∣ φ}
↔ ∀x(x ∈ A →
φ)) |
|
Theorem | ssabral 3337* |
The relation for a subclass of a class abstraction is equivalent to
restricted quantification. (Contributed by NM, 6-Sep-2006.)
|
⊢ (A ⊆ {x ∣ φ}
↔ ∀x ∈ A φ) |
|
Theorem | ss2abi 3338 |
Inference of abstraction subclass from implication. (Contributed by NM,
31-Mar-1995.)
|
⊢ (φ
→ ψ)
⇒ ⊢ {x ∣ φ} ⊆
{x ∣
ψ} |
|
Theorem | ss2abdv 3339* |
Deduction of abstraction subclass from implication. (Contributed by NM,
29-Jul-2011.)
|
⊢ (φ
→ (ψ → χ)) ⇒ ⊢ (φ
→ {x ∣ ψ}
⊆ {x
∣ χ}) |
|
Theorem | abssdv 3340* |
Deduction of abstraction subclass from implication. (Contributed by NM,
20-Jan-2006.)
|
⊢ (φ
→ (ψ → x ∈ A)) ⇒ ⊢ (φ
→ {x ∣ ψ}
⊆ A) |
|
Theorem | abssi 3341* |
Inference of abstraction subclass from implication. (Contributed by NM,
20-Jan-2006.)
|
⊢ (φ
→ x ∈ A) ⇒ ⊢ {x ∣ φ}
⊆ A |
|
Theorem | ss2rab 3342 |
Restricted abstraction classes in a subclass relationship. (Contributed
by NM, 30-May-1999.)
|
⊢ ({x ∈ A ∣ φ}
⊆ {x
∈ A
∣ ψ} ↔ ∀x ∈ A (φ → ψ)) |
|
Theorem | rabss 3343* |
Restricted class abstraction in a subclass relationship. (Contributed
by NM, 16-Aug-2006.)
|
⊢ ({x ∈ A ∣ φ}
⊆ B
↔ ∀x ∈ A (φ →
x ∈
B)) |
|
Theorem | ssrab 3344* |
Subclass of a restricted class abstraction. (Contributed by NM,
16-Aug-2006.)
|
⊢ (B ⊆ {x ∈ A ∣ φ}
↔ (B ⊆ A ∧ ∀x ∈ B φ)) |
|
Theorem | ssrabdv 3345* |
Subclass of a restricted class abstraction (deduction rule).
(Contributed by NM, 31-Aug-2006.)
|
⊢ (φ
→ B ⊆ A)
& ⊢ ((φ
∧ x ∈ B) →
ψ) ⇒ ⊢ (φ
→ B ⊆ {x ∈ A ∣ ψ}) |
|
Theorem | rabssdv 3346* |
Subclass of a restricted class abstraction (deduction rule).
(Contributed by NM, 2-Feb-2015.)
|
⊢ ((φ
∧ x ∈ A ∧ ψ) →
x ∈
B) ⇒ ⊢ (φ
→ {x ∈ A ∣ ψ}
⊆ B) |
|
Theorem | ss2rabdv 3347* |
Deduction of restricted abstraction subclass from implication.
(Contributed by NM, 30-May-2006.)
|
⊢ ((φ
∧ x ∈ A) →
(ψ → χ)) ⇒ ⊢ (φ
→ {x ∈ A ∣ ψ}
⊆ {x
∈ A
∣ χ}) |
|
Theorem | ss2rabi 3348 |
Inference of restricted abstraction subclass from implication.
(Contributed by NM, 14-Oct-1999.)
|
⊢ (x ∈ A →
(φ → ψ)) ⇒ ⊢ {x ∈ A ∣ φ}
⊆ {x
∈ A
∣ ψ} |
|
Theorem | rabss2 3349* |
Subclass law for restricted abstraction. (Contributed by NM,
18-Dec-2004.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)
|
⊢ (A ⊆ B →
{x ∈
A ∣
φ} ⊆ {x ∈ B ∣ φ}) |
|
Theorem | ssab2 3350* |
Subclass relation for the restriction of a class abstraction.
(Contributed by NM, 31-Mar-1995.)
|
⊢ {x ∣ (x ∈ A ∧ φ)} ⊆ A |
|
Theorem | ssrab2 3351* |
Subclass relation for a restricted class. (Contributed by NM,
19-Mar-1997.)
|
⊢ {x ∈ A ∣ φ}
⊆ A |
|
Theorem | rabssab 3352 |
A restricted class is a subclass of the corresponding unrestricted class.
(Contributed by Mario Carneiro, 23-Dec-2016.)
|
⊢ {x ∈ A ∣ φ}
⊆ {x
∣ φ} |
|
Theorem | uniiunlem 3353* |
A subset relationship useful for converting union to indexed union using
dfiun2 4001 or dfiun2g 3999 and intersection to indexed intersection
using
dfiin2 4002. (Contributed by NM, 5-Oct-2006.) (Proof
shortened by Mario
Carneiro, 26-Sep-2015.)
|
⊢ (∀x ∈ A B ∈ D →
(∀x
∈ A
B ∈
C ↔ {y ∣ ∃x ∈ A y = B} ⊆ C)) |
|
Theorem | dfpss2 3354 |
Alternate definition of proper subclass. (Contributed by NM,
7-Feb-1996.)
|
⊢ (A ⊊
B ↔ (A ⊆ B ∧ ¬ A = B)) |
|
Theorem | dfpss3 3355 |
Alternate definition of proper subclass. (Contributed by NM, 7-Feb-1996.)
(Proof shortened by Andrew Salmon, 26-Jun-2011.)
|
⊢ (A ⊊
B ↔ (A ⊆ B ∧ ¬ B ⊆ A)) |
|
Theorem | psseq1 3356 |
Equality theorem for proper subclass. (Contributed by NM, 7-Feb-1996.)
|
⊢ (A =
B → (A ⊊ C
↔ B ⊊ C)) |
|
Theorem | psseq2 3357 |
Equality theorem for proper subclass. (Contributed by NM, 7-Feb-1996.)
|
⊢ (A =
B → (C ⊊ A
↔ C ⊊ B)) |
|
Theorem | psseq1i 3358 |
An equality inference for the proper subclass relationship.
(Contributed by NM, 9-Jun-2004.)
|
⊢ A =
B ⇒ ⊢ (A ⊊
C ↔ B ⊊ C) |
|
Theorem | psseq2i 3359 |
An equality inference for the proper subclass relationship.
(Contributed by NM, 9-Jun-2004.)
|
⊢ A =
B ⇒ ⊢ (C ⊊
A ↔ C ⊊ B) |
|
Theorem | psseq12i 3360 |
An equality inference for the proper subclass relationship.
(Contributed by NM, 9-Jun-2004.)
|
⊢ A =
B
& ⊢ C =
D ⇒ ⊢ (A ⊊
C ↔ B ⊊ D) |
|
Theorem | psseq1d 3361 |
An equality deduction for the proper subclass relationship.
(Contributed by NM, 9-Jun-2004.)
|
⊢ (φ
→ A = B) ⇒ ⊢ (φ
→ (A ⊊ C ↔ B
⊊ C)) |
|
Theorem | psseq2d 3362 |
An equality deduction for the proper subclass relationship.
(Contributed by NM, 9-Jun-2004.)
|
⊢ (φ
→ A = B) ⇒ ⊢ (φ
→ (C ⊊ A ↔ C
⊊ B)) |
|
Theorem | psseq12d 3363 |
An equality deduction for the proper subclass relationship.
(Contributed by NM, 9-Jun-2004.)
|
⊢ (φ
→ A = B)
& ⊢ (φ
→ C = D) ⇒ ⊢ (φ
→ (A ⊊ C ↔ B
⊊ D)) |
|
Theorem | pssss 3364 |
A proper subclass is a subclass. Theorem 10 of [Suppes] p. 23.
(Contributed by NM, 7-Feb-1996.)
|
⊢ (A ⊊
B → A ⊆ B) |
|
Theorem | pssne 3365 |
Two classes in a proper subclass relationship are not equal. (Contributed
by NM, 16-Feb-2015.)
|
⊢ (A ⊊
B → A ≠ B) |
|
Theorem | pssssd 3366 |
Deduce subclass from proper subclass. (Contributed by NM,
29-Feb-1996.)
|
⊢ (φ
→ A ⊊ B) ⇒ ⊢ (φ
→ A ⊆ B) |
|
Theorem | pssned 3367 |
Proper subclasses are unequal. Deduction form of pssne 3365.
(Contributed by David Moews, 1-May-2017.)
|
⊢ (φ
→ A ⊊ B) ⇒ ⊢ (φ
→ A ≠ B) |
|
Theorem | sspss 3368 |
Subclass in terms of proper subclass. (Contributed by NM,
25-Feb-1996.)
|
⊢ (A ⊆ B ↔
(A ⊊ B ∨ A = B)) |
|
Theorem | pssirr 3369 |
Proper subclass is irreflexive. Theorem 7 of [Suppes] p. 23.
(Contributed by NM, 7-Feb-1996.)
|
⊢ ¬ A
⊊ A |
|
Theorem | pssn2lp 3370 |
Proper subclass has no 2-cycle loops. Compare Theorem 8 of [Suppes]
p. 23. (Contributed by NM, 7-Feb-1996.) (Proof shortened by Andrew
Salmon, 26-Jun-2011.)
|
⊢ ¬ (A
⊊ B ∧ B ⊊
A) |
|
Theorem | sspsstri 3371 |
Two ways of stating trichotomy with respect to inclusion. (Contributed by
NM, 12-Aug-2004.)
|
⊢ ((A ⊆ B ∨ B ⊆ A) ↔
(A ⊊ B ∨ A = B ∨ B ⊊
A)) |
|
Theorem | ssnpss 3372 |
Partial trichotomy law for subclasses. (Contributed by NM, 16-May-1996.)
(Proof shortened by Andrew Salmon, 26-Jun-2011.)
|
⊢ (A ⊆ B →
¬ B ⊊ A) |
|
Theorem | psstr 3373 |
Transitive law for proper subclass. Theorem 9 of [Suppes] p. 23.
(Contributed by NM, 7-Feb-1996.)
|
⊢ ((A
⊊ B ∧ B ⊊
C) → A ⊊ C) |
|
Theorem | sspsstr 3374 |
Transitive law for subclass and proper subclass. (Contributed by NM,
3-Apr-1996.)
|
⊢ ((A ⊆ B ∧ B ⊊
C) → A ⊊ C) |
|
Theorem | psssstr 3375 |
Transitive law for subclass and proper subclass. (Contributed by NM,
3-Apr-1996.)
|
⊢ ((A
⊊ B ∧ B ⊆ C) →
A ⊊ C) |
|
Theorem | psstrd 3376 |
Proper subclass inclusion is transitive. Deduction form of psstr 3373.
(Contributed by David Moews, 1-May-2017.)
|
⊢ (φ
→ A ⊊ B)
& ⊢ (φ
→ B ⊊ C) ⇒ ⊢ (φ
→ A ⊊ C) |
|
Theorem | sspsstrd 3377 |
Transitivity involving subclass and proper subclass inclusion.
Deduction form of sspsstr 3374. (Contributed by David Moews,
1-May-2017.)
|
⊢ (φ
→ A ⊆ B)
& ⊢ (φ
→ B ⊊ C) ⇒ ⊢ (φ
→ A ⊊ C) |
|
Theorem | psssstrd 3378 |
Transitivity involving subclass and proper subclass inclusion.
Deduction form of psssstr 3375. (Contributed by David Moews,
1-May-2017.)
|
⊢ (φ
→ A ⊊ B)
& ⊢ (φ
→ B ⊆ C) ⇒ ⊢ (φ
→ A ⊊ C) |
|
Theorem | npss 3379 |
A class is not a proper subclass of another iff it satisfies a
one-directional form of eqss 3287. (Contributed by Mario Carneiro,
15-May-2015.)
|
⊢ (¬ A
⊊ B ↔ (A ⊆ B → A =
B)) |
|
2.1.12 The difference, union, and intersection
of two classes
|
|
Theorem | difeq12 3380 |
Equality theorem for class difference. (Contributed by FL,
31-Aug-2009.)
|
⊢ ((A =
B ∧
C = D)
→ (A ∖ C) =
(B ∖
D)) |
|
Theorem | difeq1i 3381 |
Inference adding difference to the right in a class equality.
(Contributed by NM, 15-Nov-2002.)
|
⊢ A =
B ⇒ ⊢ (A ∖ C) =
(B ∖
C) |
|
Theorem | difeq2i 3382 |
Inference adding difference to the left in a class equality.
(Contributed by NM, 15-Nov-2002.)
|
⊢ A =
B ⇒ ⊢ (C ∖ A) =
(C ∖
B) |
|
Theorem | difeq12i 3383 |
Equality inference for class difference. (Contributed by NM,
29-Aug-2004.)
|
⊢ A =
B
& ⊢ C =
D ⇒ ⊢ (A ∖ C) =
(B ∖
D) |
|
Theorem | difeq1d 3384 |
Deduction adding difference to the right in a class equality.
(Contributed by NM, 15-Nov-2002.)
|
⊢ (φ
→ A = B) ⇒ ⊢ (φ
→ (A ∖ C) =
(B ∖
C)) |
|
Theorem | difeq2d 3385 |
Deduction adding difference to the left in a class equality.
(Contributed by NM, 15-Nov-2002.)
|
⊢ (φ
→ A = B) ⇒ ⊢ (φ
→ (C ∖ A) =
(C ∖
B)) |
|
Theorem | difeq12d 3386 |
Equality deduction for class difference. (Contributed by FL,
29-May-2014.)
|
⊢ (φ
→ A = B)
& ⊢ (φ
→ C = D) ⇒ ⊢ (φ
→ (A ∖ C) =
(B ∖
D)) |
|
Theorem | difeqri 3387* |
Inference from membership to difference. (Contributed by NM,
17-May-1998.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)
|
⊢ ((x ∈ A ∧ ¬ x ∈ B) ↔
x ∈
C) ⇒ ⊢ (A ∖ B) =
C |
|
Theorem | eldifi 3388 |
Implication of membership in a class difference. (Contributed by NM,
29-Apr-1994.)
|
⊢ (A ∈ (B ∖ C) →
A ∈
B) |
|
Theorem | eldifn 3389 |
Implication of membership in a class difference. (Contributed by NM,
3-May-1994.)
|
⊢ (A ∈ (B ∖ C) →
¬ A ∈ C) |
|
Theorem | elndif 3390 |
A set does not belong to a class excluding it. (Contributed by NM,
27-Jun-1994.)
|
⊢ (A ∈ B →
¬ A ∈ (C ∖ B)) |
|
Theorem | neldif 3391 |
Implication of membership in a class difference. (Contributed by NM,
28-Jun-1994.)
|
⊢ ((A ∈ B ∧ ¬ A ∈ (B ∖ C)) →
A ∈
C) |
|
Theorem | difdif 3392 |
Double class difference. Exercise 11 of [TakeutiZaring] p. 22.
(Contributed by NM, 17-May-1998.)
|
⊢ (A ∖ (B ∖ A)) =
A |
|
Theorem | difss 3393 |
Subclass relationship for class difference. Exercise 14 of
[TakeutiZaring] p. 22.
(Contributed by NM, 29-Apr-1994.)
|
⊢ (A ∖ B) ⊆ A |
|
Theorem | difssd 3394 |
A difference of two classes is contained in the minuend. Deduction form
of difss 3393. (Contributed by David Moews, 1-May-2017.)
|
⊢ (φ
→ (A ∖ B) ⊆ A) |
|
Theorem | difss2 3395 |
If a class is contained in a difference, it is contained in the minuend.
(Contributed by David Moews, 1-May-2017.)
|
⊢ (A ⊆ (B ∖ C) →
A ⊆
B) |
|
Theorem | difss2d 3396 |
If a class is contained in a difference, it is contained in the minuend.
Deduction form of difss2 3395. (Contributed by David Moews,
1-May-2017.)
|
⊢ (φ
→ A ⊆ (B ∖ C)) ⇒ ⊢ (φ
→ A ⊆ B) |
|
Theorem | ssdifss 3397 |
Preservation of a subclass relationship by class difference. (Contributed
by NM, 15-Feb-2007.)
|
⊢ (A ⊆ B →
(A ∖
C) ⊆
B) |
|
Theorem | ddif 3398 |
Double complement under universal class. Exercise 4.10(s) of
[Mendelson] p. 231. (Contributed by
NM, 8-Jan-2002.)
|
⊢ (V ∖ (V
∖ A)) =
A |
|
Theorem | ssconb 3399 |
Contraposition law for subsets. (Contributed by NM, 22-Mar-1998.)
|
⊢ ((A ⊆ C ∧ B ⊆ C) →
(A ⊆
(C ∖
B) ↔ B ⊆ (C ∖ A))) |
|
Theorem | sscon 3400 |
Contraposition law for subsets. Exercise 15 of [TakeutiZaring] p. 22.
(Contributed by NM, 22-Mar-1998.)
|
⊢ (A ⊆ B →
(C ∖
B) ⊆
(C ∖
A)) |