2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/227121When many fundamental strings are stacked together, they puff up into D-branes. BIons and giant gravitons are the examples of such D-brane configurations that arise from coincident strings. We propose and demonstrate analogous transitions in topological string theory. Such transitions can also be understood in terms of the Fourier transform of D-brane amplitudes.21 pages; v.2 references added; v.3 reference added; v.4 minor corrections; v.5 substantial rewritingHigh Energy Physics - Theorytext