# Thread: how to describe time period relationship?(Subset intersection)

1. ## how to describe time period relationship?(Subset intersection)

Suppose I have four time periods as follows:

Period A: from July 1st, 2010 to July 10th, 2010,
Period B: from July 3rd, 2010 to July 12th, 2010.
Period C: from July 3rd, 2010 to July 9th, 2010.
Period D: from July 15th, 2010 to July 19th, 2010.

Can I say:

1) Period C is the subset of period A.
2) There is an intersection between period A and B.
3) There is no intersection between period A and D.

or any suggestions on words subset, intersection and union of set?

How to describe time period relationship?

Many thanks.

2. ## Re: how to describe time period relationship?(Subset intersection)

Isn't this a maths question?

Rover

3. ## Re: how to describe time period relationship?(Subset intersection)

Originally Posted by Rover_KE
Isn't this a maths question?

Rover
Yes. Finite Mathematics--vectors, sets, permutations, combinations, etc.

4. ## Re: how to describe time period relationship?(Subset intersection)

Originally Posted by Rover_KE
Isn't this a maths question?

Rover
Yes, kind of. But actually, I work in a software company as a developer. I am required to write some design documents. So I just want to check whether I used these words correctly.

Thank you.

5. ## Re: how to describe time period relationship?(Subset intersection)

Originally Posted by tobysky
1) Period C is a subset of period A. It's not the only subset, so you can't say it's 'the' subset unless you've already mentioned a subset. If the question read, "Identify the subset in the four sentences", you could use 'the'.

2) There is an intersection between period A and B.
3) There is no intersection between period A and D.

or any suggestions on words subset, intersection and union of set?

How to describe time period relationship?

Many thanks.
1. Period A includes all the time in period B.
2. Period A includes some of the time in period B and vice versa.
3. Period A and Period D do not share any time period. / There is no overlap of time periods in Periods A and D.