Del Vento So to reiterate: what are the differences and similarities between the A major and C minor chords in the context of "recognizing the notes quickly without pain"? And why do they have such differences and similarities? And how can you use such differences and similarities in practical playing?
C minor is c - e flat - g.
A major is a - c sharp - e
For impro or semi impro or composing … we can momentarily ignore chord name, and assume we're playing a tune based on the 'key' of c minor. Also assume we know the c minor scale, which then allows the c minor chord to be known.
Taking c - e flat - g, and sharping the first two notes to get c sharp - e - g, we can sometimes take a punt that using sharp - e - g could be workable (or sounding 'alright') while playing in the key of c minor. That could be due to the relative small change made by semi-tone offseting.
And then, if we go ahead to change the 'g' to an 'a', to get c sharp - e - a, then this note combo … after doing a cyclic shift is a - c sharp - e, so either of those cyclic permutations are A-major chord, which could be workable.
But all that sort of thing is relating to generating music ….. while learning to play the piano is not always clear in the meaning, because playing the piano with sheet music only and then memorising counts as learning to play.
Even if takes ages for somebody to remember sequence of music with two hands relatively independent, then that certainly counts as learning to play the piano. Even one hand or one finger piano playing is learning, as there are different stages/levels etc of learning to play a piano.
You invoked an excellent reminder in the music composing/generation area, where song type music generation probably does require some thought process that computer/a.i. algorithms haven't reached. A.I. currently isn't at a level that is anywhere close to song or symphony generation ….. as in of relatively 'good' level of complexity …. not those basic A.I. 'orchestral' games sounding battle/legion music that some A.I. came up with … which is a very nice start, but far from relatively sophisticated/complex.
The reason for mentioning of a particular kind of process is … at the moment, the sophisticated process aren't in a form that can be translated into an algorithm procedure, as humans learn and apply music context (and even then adding suitable/workable lyrics for particular music for songs) in ways that the A.I. plus programming can't match yet.
The above can look like rambling, and probably some of it is rambling, which goes to show self awareness in the human side if things.