Given the following context:

Tchaikovsky struggled with sonata form. Its principle of organic growth through the interplay of musical themes was alien to Russian practice. The traditional argument that Tchaikovsky seemed unable to develop themes in this manner fails to consider this point; it also discounts the possibility that Tchaikovsky might have intended the development passages in his large-scale works to act as "enforced hiatuses" to build tension, rather than grow organically as smoothly progressive musical arguments.According to Brown and musicologists Hans Keller and Daniel Zhitomirsky, Tchaikovsky found his solution to large-scale structure while composing the Fourth Symphony. He essentially sidestepped thematic interaction and kept sonata form only as an "outline," as Zhitomirsky phrases it. Within this outline, the focus centered on periodic alternation and juxtaposition. Tchaikovsky placed blocks of dissimilar tonal and thematic material alongside one another, with what Keller calls "new and violent contrasts" between musical themes, keys, and harmonies. This process, according to Brown and Keller, builds momentum and adds intense drama. While the result, Warrack charges, is still "an ingenious episodic treatment of two tunes rather than a symphonic development of them" in the Germanic sense, Brown counters that it took the listener of the period "through a succession of often highly charged sections which added up to a radically new kind of symphonic experience" (italics Brown), one that functioned not on the basis of summation, as Austro-German symphonies did, but on one of accumulation.Partly due to the melodic and structural intricacies involved in this accumulation and partly due to the composer's nature, Tchaikovsky's music became intensely expressive. This intensity was entirely new to Russian music and prompted some Russians to place Tchaikovsky's name alongside that of Dostoyevsky. German musicologist Hermann Kretzschmar credits Tchaikovsky in his later symphonies with offering "full images of life, developed...

answer the following question:

What is the first name of the person who, with Brown, said that Tchaikovsky's process builds momentum and adds intense drama? 

Hans