That we are conscious of a part of our cognitions a priori is a fact, strictly proved by Kant.
Die von ihm streng bewiesene Thatsache, daß ein Theil unserer Erkenntnisse uns a priori bewußt ist, läßt gar keine andere Erklärung zu, als daß diese die Formen unsers Intellekts ausmachen:
The fact, strictly proved by him, that we are conscious of a part of our cognitions a priori admits of no other explanation than that these constitute the forms of our intellect:
The subject of the third sentence of the paragraph, »Die von ihm streng bewiesene Thatsache, daß ein Theil unserer Erkenntnisse uns a priori bewußt ist«: the sentence presupposes the fact and attributes its proof to Kant, »ihm«, named in the first sentence, and the map takes the presupposition as a claim because the paragraph's argument rests on it. What the sentence predicates of the fact is c-schopenhauer-a-priori-cognitions-explained-only-as-forms-of-the-intellect. The claim is premise 1 of the checked argument a-schopenhauer-cognitions-a-priori-are-the-intellects-own-forms. Kant's own statement of it in the map is for space, A 24 / B 38 (c-kant-space-a-priori); no link is set, since this statement names no cognition and Kant's names one, and the comparison x-thing-in-itself says so.