We generalize the method of our recent paper on the large-spin expansions of Gubser-Klebanov-Polyakov (GKP) strings to the large-spin and large-winding expansions of finitesize giant magnons and finite-size single spikes. By expressing the energies of long open strings in R × S 2 in terms of Lambert's W-function, we compute the leading, subleading and next-to-subleading series of classical exponential corrections to the dispersion relations of Hofman-Maldacena giant magnons and infinite-winding single spikes. We also compute the corresponding expansions in the doubled regions of giant magnons and single spikes that are respectively obtained when their angular and linear velocities become smaller or greater than unity. * E-mails: mflorato@phys.uoa.gr, glinard@inp.demokritos.gr. arXiv:1406.0796v4 [hep-th] 11 Nov 2015 E Lambert's W-Function 36 F Elliptic Integrals and Jacobian Elliptic Functions 381 We shall employ the following convention in our paper: E, J, p = ∞ and v, ω = 1 will denote infinite size (as obtained by computing the lim J/p→∞ , lim v/ω→1 ) and E, J, p → ∞, v, ω → 1 will denote large but still finite size.2 The compact su (2) sector of N = 4 super Yang-Mills consists of the single-trace operators Tr Z J X M , where X , Y, Z are the three complex scalar fields of N = 4 SYM, composed out of the six real scalars Φ of the theory. The su (2) sector is dual to (closed) strings that rotate in R × S 3 ⊂ AdS5 × S 5 and its one-loop dilatation operator is given by the Hamiltonian of the ferromagnetic XXX 1/2 Heisenberg spin chain.