This version of Set Theory is revision 6c40575 (2021-10-30), with
content generated from Open Logic Text revision 2323423 (2024-
01-24).
Section 2.3 Some Important Sets.
What is the typo:
It is less obvious that R ⊊ Q,
i.e., that there are some real numbers which are not rational.
Proposed correction:
It is less obvious that R ⊈ Q,
i.e., that there are some real numbers which are not rational.
Comments:
The suggested correction is consistent with:
Definition 2.5 (Subset). If every member of a set A is also
a member of B, then we say that A is a subset of B, and write
A ⊆ B. If A is not a subset of B we write A ⊈ B. If A ⊆ B but
A ≠ B, we write A ⊊ B and say that A is a proper subset of B.
It is not the case that R is a proper subset of Q.
rzach
commented
9 months ago
Typo location:
This version of Set Theory is revision 6c40575 (2021-10-30), with content generated from Open Logic Text revision 2323423 (2024- 01-24).
Section 2.3 Some Important Sets.
What is the typo:
It is less obvious that R ⊊ Q, i.e., that there are some real numbers which are not rational.
Proposed correction:
It is less obvious that R ⊈ Q, i.e., that there are some real numbers which are not rational.
Comments:
The suggested correction is consistent with:
Definition 2.5 (Subset). If every member of a set A is also a member of B, then we say that A is a subset of B, and write A ⊆ B. If A is not a subset of B we write A ⊈ B. If A ⊆ B but A ≠ B, we write A ⊊ B and say that A is a proper subset of B.
It is not the case that R is a proper subset of Q.