MHB Questions about sets and subsets

  • Thread starter Thread starter shle
  • Start date Start date
  • Tags Tags
    Sets Subsets
AI Thread Summary
The discussion centers on proving set relationships involving subsets X and Y of a universal set U. Specifically, it addresses the implication that if X is a subset of Y, then the complement of Y is a subset of the complement of X. A suggested approach includes using a Venn diagram to visualize the relationship, although a textual explanation suffices. The explanation provided clarifies that any element not in Y is also not in X, thereby confirming the subset relationship for their complements. This proof emphasizes the logical connections between subsets and their complements in set theory.
shle
Messages
4
Reaction score
0
Hi, the question goes as follows:

Given two subsets X and Y of a universal set U, prove that: (refer to picture)

I'm having particular trouble on D and E, if anyone can clear this up or provide some clarification for me that would be appreciated! I know a venn diagram might not be possible here so just an explanation is ok

Thank you!​
 

Attachments

  • Section218.jpg
    Section218.jpg
    72.5 KB · Views: 74
Mathematics news on Phys.org
shle said:
Hi, the question goes as follows:

Given two subsets X and Y of a universal set U, prove that: (refer to picture)

I'm having particular trouble on D and E, if anyone can clear this up or provide some clarification for me that would be appreciated! I know a venn diagram might not be possible here so just an explanation is ok

Thank you!​

d) Show that \( X\subseteq Y\) implies \(\overline{Y} \subseteq \overline{X}\)

Other than the Venn diagram where the region representing \(X\) is inside that representin \(Y\) so that the coplement of \(Y\) is contained within the complement of \(X\) (You are strongly recomended to draw the diagram), Consider any \(z \not\in Y\), then it is in \(\overline{Y}\), but because \( X\subseteq Y\) it is also not in \(X\), so is in \(\overline{X}\), which proves the result.

CB
 
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Back
Top