Feel free to ask any questions etc. here :)

I noticed that you use the spelling "contraposative" consistently. I'd only known this as "contrapositive", and Wiktionary agrees: https://en.wiktionary.org/wiki/contrapositive . But I find lots of web hits for "contraposative", so I suspect it's more than just a common typo. Did you learn this specific form from some specific source that contrasted the two?