RP2

[thomas-lamiaux]

Add RP2, in progress

[thomas-lamiaux]

@aljungstrom I miss H4 RP2 to do my proof

[thomas-lamiaux]

@mortberg Hi, just to tell you that the proof are basically done up to

• @aljungstrom add a full characterization of H^n (RP²), there is only 1-3 for the moment
• I add the following lemma . Nothing very hard just annoying, I'll come back on that when Axel is done with what is missing

About working with the Z/k, I think this prove it stills works up to a few tricks. Though it would be a bit more complicated in the general case as Axel used Bool for Z/2. But this would only change some details. The good news too, is that the scheme of the proof doesn't change and the additional properties can be proven relatively simply by level as before. Plus, having more then one object in the ideal quotienting doesn't change anything when working.

[thomas-lamiaux]

@mortberg Finally done with that !