memes

Again, for example, I am a mathematical Platonist. What beliefs of mine in that regard contradict with Marxism?

Well for one you see math as something independent, you see math existing in a vacuum.

"Contrary to metaphysics, dialectics does not regard nature as an accidental agglomeration of things, of phenomena, unconnected with, isolated from, and independent of, each other, but as a connected and integral whole, in which things, phenomena are organically connected with, dependent on, and determined by, each other.

The dialectical method therefore holds that no phenomenon in nature can be understood if taken by itself, isolated from surrounding phenomena, inasmuch as any phenomenon in any realm of nature may become meaningless to us if it is not considered in connection with the surrounding conditions, but divorced from them; and that, vice versa, any phenomenon can be understood and explained if considered in its inseparable connection with surrounding phenomena, as one conditioned by surrounding phenomena." (Dialectical and Historical Materialism)

This is my understanding of your views from what you wrote in other replies, i haven't read and don't plan to read about mathematical Platonism, we already have developed much further than whatever Plato worked with.