Definition A: That has no predecessor has "the minimal magnitude of existence".
Example: Emptiness has "the minimal magnitude of existence".
The Cardinality of Emptiness is 0.
Definition B: That has no successor has "the maximal magnitude of existence".
Example: Fullness (the opposite of Emptiness) has "the maximal magnitude of existence".
The Cardinality of Fullness is ∞.
Definition C: That has predecessor AND successor has "an intermediate magnitude of existence".
The cardinality of that has "an intermediate magnitude of existence" is x, such that 0 < x < ∞. (where < is "greater than").
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X is a placeholder for 0, x or ∞.
Definition D: In the case of Cardinality, "That has no predecessor, its cardinality is not a successor".
Example: X+0=X
Details:
5+0=5, where 0 is not a successor.
|infinite collection|+0=|infinite collection|, where 0 is not a successor.
∞+0= ∞, where 0 is not a successor.
Definition E: In the case of Cardinality, "That has no successor, its cardinality is not a predecessor".
Example: ∞-X= ∞
Details:
∞-5= ∞, where ∞ is not a predecessor.
∞-|infinite collection|= ∞, where ∞ is not a predecessor.
∞-∞= ∞, where ∞ is not a predecessor.
Definition F: A set exists at least as "That has no successor" AND "That has no predecessor".
Example: {} is a set , such that the outer "{""}" represents "That has no successor" AND the emptiness between the outer "{""}" represents "That has no predecessor".
Definition G: The cardinality of the members of a given set is defined by their "magnitude of existence" w.r.t Definition A or Definition B.
Examples: |{}|=0, |{{}}|=1, |{x,y,"banana"}|=3, |{1,2,3,4,5,…}|=non-strict cardinality, because no diverges collection of members has the magnitude of existence of "That has no successor", |{[0,1]}|=non-strict cardinality, because no converges collection of members has the magnitude of existence of "That has no successor".
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Theorem: No set is a member of itself.
Proof:
According to Definition F, a set exists even if there are no members.
According to Definition G, any Cardinality of a given set, which is defined by the magnitude of existence of some collection (or its absence),
is < ∞.
Any collection is based on members (or their absence) so no collection of members or any given member has the cardinality of ∞.
In that case the magnitude of existence of a set is not identical to any magnitude of existence of any member, and we can conclude that no set is a member of itself.
Q.E.D
In this proof we have used MP:
MP.
If P, then Q.
P.
Therefore, Q.
If
P="the cardinality of a collection (where any collection is based on members (or their absence)) < ∞",
Then.
Q=" No set is a member of itself."
P.
Therefore, Q.