- #1
lavoisier
- 177
- 24
Hi everyone,
a problem that seems mathematical in nature came to my mind at work a few days ago, and I wonder if anyone can help me with it.
Basically, we are given a schedule of when certain biological assays take place, e.g. assay A will take place each even week of the year starting on week 2, and assay B will take place every 4 weeks starting on week 1.
It's relatively easy to write out the explicit cases:
A={2,4,6...}
B={1,5,9,13,17...}
What I wanted to know was on which weeks there were no assays. Again, easy enough to write it out:
no_assays={3,7,11,...}.
And whether A and B could happen on the same week. Clearly not, as A only happens on even weeks, whereas B only happens on odd weeks.
But I wanted to make this more systematic. I started by noting that A corresponded to a 2*n pattern, with n positive integer, and B to 2*m+1, with m positive integer or zero.
Then I wondered how I could derive the pattern for no_assays (of course 4*k-1, with k positive integer) just from the patterns for A and B, without writing out the explicit cases.
Maybe not in a simple case like this one, but in a more complicated one. E.g. if there were 3 assays A, B and C, with A on weeks 3*n+1, B on weeks 4*m, C on weeks 5*p, with n, m and p positive integers, how could I determine if+when+which assays happen on the same week, and if+when there are weeks with no assays?
Is there an 'official' approach one may use for this kind of problem? Maybe something related to Diophantine equations?
Thank you!
L
a problem that seems mathematical in nature came to my mind at work a few days ago, and I wonder if anyone can help me with it.
Basically, we are given a schedule of when certain biological assays take place, e.g. assay A will take place each even week of the year starting on week 2, and assay B will take place every 4 weeks starting on week 1.
It's relatively easy to write out the explicit cases:
A={2,4,6...}
B={1,5,9,13,17...}
What I wanted to know was on which weeks there were no assays. Again, easy enough to write it out:
no_assays={3,7,11,...}.
And whether A and B could happen on the same week. Clearly not, as A only happens on even weeks, whereas B only happens on odd weeks.
But I wanted to make this more systematic. I started by noting that A corresponded to a 2*n pattern, with n positive integer, and B to 2*m+1, with m positive integer or zero.
Then I wondered how I could derive the pattern for no_assays (of course 4*k-1, with k positive integer) just from the patterns for A and B, without writing out the explicit cases.
Maybe not in a simple case like this one, but in a more complicated one. E.g. if there were 3 assays A, B and C, with A on weeks 3*n+1, B on weeks 4*m, C on weeks 5*p, with n, m and p positive integers, how could I determine if+when+which assays happen on the same week, and if+when there are weeks with no assays?
Is there an 'official' approach one may use for this kind of problem? Maybe something related to Diophantine equations?
Thank you!
L