/sci/ - Science & Math

>>11340542
You might as well start calling these threads /iec/ - is economics a science general.
What is it with undergrads and computer scientists and trying to fit in by insulting economics?

>>11301993
Homology and Cohomology measure "failure to lift" in an appropriate sense given by context.
In singular homology, you have a failure of lifting of [math]f : \Delta _n \rightarrow X[/math] where the map doesn't lift to a map from [math]\Delta _{n+1}[/math].
In de Rham cohomology, the local inverses of the [math]d[/math] operator don't lift to a global solution.
Similarly, in several complex variables, you'll mess around with Cousin problems, which are also situations of local to global lifting.
When you work over derived functors, this intuition becomes extremely explicit, and you're essentially measuring an object's failure to be injective or projective, which literally means they lift maps.

This is my intuition, feel free to insult it.

Ask in >>>/wsr/ next time.

>>11292798
No, no, no.
There are [math]n[/math] numbers coprime to 30 in [math]Z_330[/math], and [math]m[/math] numbers coprime to 30 and multiples of 11 in [math]Z_330[/math].
If [math]s(x)[/math] returns the x-th number coprime to 30, and [math]s*(x)[/math] returns the x-th number coprime to 30 and a multiple of 11, we have the relation [math]s(a)+330=s(a+n)=s(b)+330=s(b+m)[/math], get it?
>>11292867
You absolutely should still call the labs, tho.
>>11294305
Now listen, I'm not a biologist, and I'm answering based on what I recall from high school.
But wasn't RNA prior to DNA? First you had shitty little things with RNA, and then you had shitty little things with DNA?