From: zuhair on
NST2: is the set of all sentences entailed (from FOL with identity
and e) by the following non logical axioms below the following
definition of the notion "set" denoted by M:

Define(set): x is a set <-> Exist y ( x e y )

Define(M): Mx <-> x is a set.

1. Extensionality: for all z ( z e y <-> z e x) -> x=y

2. Foundation: Exist y y e x -> Exist y (y e x & y disjoint x)

3. Classes: If phi is a formula in which at least y is free, and in
which x is not free, then all closures of

Exist x for all y ( y e x <-> My phi )

are axioms.

4. Set existence: Exist x: x is a set.

Q is a proper substring of phi, means that Q is a substring of phi
and Q is not the formula phi.

Q is said to be a proper subformula of phi if
Q is a proper substring of phi that is a formula, that has the same
principal free variable as phi, and the set of all parameters of Q is
a subset of the set of all parameters of phi.

5. Sets:If phi is a formula in which at least y or z are free, and in
which c is not free, with parameters x1,...,xn, and constants
k1,...,kp , and Q1,...,Qm are all proper subformulas of phi, then all
closures of:

c={y|phi} &
Mx1,...,Mxn & Mk1,...,Mkp
for all c,z ((c={y|phi} & c subclass z) -> ~ phi(z)) &
~for all x ( Mx ->Exist y (phi(y) & x e y)) &
~for all y (Myphi<->MyQ1)&...&~for all y(Myphi<->MyQm))

-> Mc

are axioms.

Theory definition finished/

Theorems with proofs shall be posted later.

Zuhair
From: zuhair on
NST2: is the set of all sentences entailed (from FOL with identity
and e) by the following non logical axioms below the following
definition of the notion "set" denoted by M:

Define(set): x is a set <-> Exist y ( x e y )

Define(M): Mx <-> x is a set.

1. Extensionality: for all z ( z e y <-> z e x) -> x=y

2. Foundation: Exist y y e x -> Exist y (y e x & y disjoint x)

3. Classes: If phi is a formula in which at least y is free, and in
which x is not free, then all closures of

Exist x for all y ( y e x <-> My phi )

are axioms.

4. Set existence: Exist x: x is a set.

Q is a proper substring of phi, means that Q is a substring of phi
and Q is not the formula phi.

Q is said to be a proper subformula of phi if
Q is a proper substring of phi that is a formula, that has the same
principal free variable as phi, and the set of all parameters of Q is
a subset of the set of all parameters of phi.

5. Sets:If phi is a formula in which at least y or z are free, and in
which c is not free, with parameters x1,...,xn, and constants
k1,...,kp , and Q1,...,Qm are all proper subformulas of phi, then all
closures of:

c={y|phi} &
Mx1,...,Mxn & Mk1,...,Mkp
for all c,z ((c={y|phi} & c subclass z) -> ~ phi(z)) &
~for all x ( Mx ->Exist y (phi(y) & x e y)) &
~for all y (Myphi<->MyQ1)&...&~for all y(Myphi<->MyQm)

-> Mc

are axioms.

Theory definition finished/

Theorems with proofs shall be posted later.

Zuhair
From: zuhair on
NST2: is the set of all sentences entailed (from FOL with identity
and e) by the following non logical axioms below the following
definition of the notion "set" denoted by M:

Define(set): x is a set <-> Exist y ( x e y )

Define(M): Mx <-> x is a set.

1. Extensionality: for all z ( z e y <-> z e x) -> x=y

2. Foundation: Exist y y e x -> Exist y (y e x & y disjoint x)

3. Classes: If phi is a formula in which at least y is free, and in
which x is not free, then all closures of

Exist x for all y ( y e x <-> My phi )

are axioms.

Define: x={y|phi} <-> for all y ( y e x <-> My phi )

4. Set existence: Exist x: x is a set.

Q is a proper substring of phi, means that Q is a substring of phi
and Q is not the formula phi.

Q is said to be a proper subformula of phi if
Q is a proper substring of phi that is a formula, that has the same
principal free variable as phi, and the set of all parameters of Q is
a subset of the set of all parameters of phi.

5. Sets:If phi is a formula in which at least y or z are free, and in
which c is not free, with parameters x1,...,xn, and constants
k1,...,kp , and Q1,...,Qm are all proper subformulas of phi, then all
closures of:

c={y|phi} &
Mx1,...,Mxn & Mk1,...,Mkp
for all c,z ((c={y|phi} & c subclass z) -> ~ phi(z)) &
~for all x ( Mx ->Exist y (phi(y) & x e y)) &
~for all y (Myphi<->MyQ1)&...&~for all y(Myphi<->MyQm)

-> Mc

are axioms.

Theory definition finished/

Theorems with proofs shall be posted later.

Zuhair
From: zuhair on
Theorems:

theorem: Exist x for all y ( y e x <-> y is a set )
proof: let phi<-> y is a set
substitute in classes.QED

theorem: Exist! x for all y ( y e x <-> y is a set )
proof: Extensionality

Define(V):- x=V <-> for all y ( y e x <-> y is a set )

theorem: Exist x for all y ~ y e x
proof:let phi <-> ~y=y
substitute in classes.QED

theorem: Exist! x for all y ~ y e x
proof: Extensionality

Define(0):- x=0 <-> for all y ( ~ y e x )

theorem: for every set a Exist x For all y ( y e x <-> y=a )
proof: let phi <-> y=a
since a is a set then from classes we'll have the set theorem
above.QED

theorem: for every set a Exist! x For all y ( y e x <-> y=a )
proof: Extensionality

Define: x={a} <-> for all y ( y e x <-> y=a )

theorem: for all x: ~ x e x
proof: suppose Exist x: x e x
then {x} would not be disjoint of x
violating foundation.

from that we have ~ V e V.

Now it is clear that from classes we can have a class that is an
unordered pair of any two sets, from that we can define ordered pair
in Kuratowski manner, also we can separation and replacement of sets,
unions both finite and infinite also can be defined, but all these are
classes the set-hood of which is not yet determined.

theorem: 0 is a set.
proof: let phi<-> ~y=y
substitute in Sets and we get
c={y|~y=y}
Now ~y=y has no parameter and no constant in it

so we need to check the following first:

for all c,z ((c={y|~y=y} & c subclass z) -> z=z))

which is trivially true.

now we check the next condition:

~for all x ( Mx ->Exist y (~y=y & x e y))

since from axiom 3 we do have at least on set existing, then the above
condition would be fulfilled since Exist y (~y=y & x e y) is trivially
false, then
for all x ( Mx ->Exist y (~y=y & x e y)) is trivially false , so its
negation is ture.

Now we check the proper subformulas condition, now the only proper
subformula of ~y=y is the formula y=y so we only need to prove the
following:

~for all y (My~y=y<->Myy=y)

since there exist at least one set (axiom 3) then the above sentence
is trivially true.

thus all conditions in the antecedent of SETS schema are fulfilled,
thus
the class {y|~y=y} is a set, thus 0 is a set.

pairing,union,power,separation and replacement of sets all can be
proved in this theory, so is infinity . Proofs shall be posted later.

So it appears as if MK is a equivalent to this theory?

Zuhair





From: zuhair on
NST2: is the set of all sentences entailed (from FOL with identity
and e) by the following non logical axioms below the following
definition of the notion "set" denoted by M:

Define(set): x is a set <-> Exist y ( x e y )

Define(M): Mx <-> x is a set.

1. Extensionality: for all z ( z e y <-> z e x) -> x=y

2. Foundation: Exist y y e x -> Exist y (y e x & y disjoint x)

3. Classes: If phi is a formula in which at least y is free, and in
which x is not free, then all closures of

Exist x for all y ( y e x <-> My phi )

are axioms.

Define: x={y|phi} <-> for all y ( y e x <-> My phi )

4. Set existence: Exist x: x is a set.

Q is a proper substring of phi, means that Q is a substring of phi
and Q is not the formula phi.

Q is said to be a proper subformula of phi if
Q is a proper substring of phi that is a formula, that has the same
principal free variable as phi, and the set of all parameters of Q is
a subset of the set of all parameters of phi.

5. Sets:If phi is a formula in which at least y or z are free, and in
which c is not free, with parameters x1,...,xn, and constants
k1,...,kp , and Q1,...,Qm are all proper subformulas of phi, then all
closures of:

Mx1,...,Mxn & Mk1,...,Mkp
for all c,z ((c={y|phi} & c subclass z) -> ~ phi(z)) &
~for all x ( Mx ->Exist y (phi(y) & x e y)) &
~for all y (Myphi<->MyQ1)&...&~for all y(Myphi<->MyQm)

-> Exist c (Mc & for all y ( y e c <-> phi )

are axioms.

Theory definition finished/

Theorems with proofs shall be posted later.

Zuhair