Final answer:
Gustav Mahler's musical activities did not encompass the boundary-pushing experiments of atonality and twelve-tone techniques seen in contemporaries such as Arnold Schoenberg.
Step-by-step explanation:
The musical activities of Gustav Mahler did not include activities such as those pursued by other composers like Berlioz, Strauss, and Wagner, who were known for pushing the boundaries of music during their time. Mahler was a conductor, composer, and an important figure within the late-Romantic period of music, but he did not directly participate in musical experimentation akin to Arnold Schoenberg's invention of atonality and the twelve-tone technique. While contemporaries such as Berlioz, Strauss, and Wagner were considered progressives, challenging audiences with new musical ideas, Mahler's works, though complex and innovative, retained tonal coherence and did not break from the traditional tonal framework as Schoenberg did.