360 research outputs found
Charippus yinae Wang & Li 2020
No full textCharippus yinae Wang & Li, 2020 Figs 195– 213 Charippus yinae Wang & Li, 2020: 45, figs 1A–D, 2A–G. Material examined. 1♀ 15 juveniles (MHBU-ARA-00023589), CHINA: Yunnan Province, Xishuangbanna, Mengla County, Menglun Town, XTBG, tropical rainforests, 21°55’12.38’’E, 101°16’4.88’’E, 554 m elev., 4 August 2021, leg. K. Yu, W. Wang, L. Zhang & J. Zhang. Diagnosis. See Wang & Li (2020). Description. See Wang & Li (2020). Natural history. The type material of C. yinae was collected from leaf litter (Wang & Li 2020; Wang, pers. comm.). We also collected this species from tree trunks in XTBG. Distribution. China (Yunnan).Published as part of Yu, Kun, Wang, Weihang, Maddison, Wayne P. & Zhang, Junxia, 2022, Revision of the genus Charippus Thorell, 1895, with descriptions of eight new species (Araneae, Salticidae, Euophryini), pp. 151-198 in Zootaxa 5129 (2) on page 189, DOI: 10.11646/zootaxa.5129.2.1, http://zenodo.org/record/650073
On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini)
No full textWang, Weihang, Zhang, Junxia (2023): On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini). Zootaxa 5297 (3): 337-379, DOI: 10.11646/zootaxa.5297.3.2, URL: http://dx.doi.org/10.11646/zootaxa.5297.3.
FIGURES 135–138 in On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini)
No full textFIGURES 135–138. Living spiders of Euochin shenjun sp. nov.. 135–136. Holotype male; 137–138. Paratype female.Published as part of Wang, Weihang & Zhang, Junxia, 2023, On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini), pp. 337-379 in Zootaxa 5297 (3) on page 366, DOI: 10.11646/zootaxa.5297.3.2, http://zenodo.org/record/800502
FIGURES 199–203 in On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini)
No full textFIGURES 199–203. Genitalia of Euochin yangmei sp. nov.. 199–201. Left male palp of holotype, in prolateral (199), ventral (200) and retrolateral (201) view; 202–203. Epigyne of paratype, in ventral (202) and dorsal (203) view.Published as part of Wang, Weihang & Zhang, Junxia, 2023, On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini), pp. 337-379 in Zootaxa 5297 (3) on page 375, DOI: 10.11646/zootaxa.5297.3.2, http://zenodo.org/record/800502
Approximating Submodular k-Partition via Principal Partition Sequence
No full textIn submodular k-partition, the input is a submodular function f:2^V → ℝ_{≥ 0} (given by an evaluation oracle) along with a positive integer k and the goal is to find a partition of the ground set V into k non-empty parts V_1, V_2, …, V_k in order to minimize ∑_{i=1}^k f(V_i). Narayanan, Roy, and Patkar [Narayanan et al., 1996] designed an algorithm for submodular k-partition based on the principal partition sequence and showed that the approximation factor of their algorithm is 2 for the special case of graph cut functions (which was subsequently rediscovered by Ravi and Sinha [R. Ravi and A. Sinha, 2008]). In this work, we study the approximation factor of their algorithm for three subfamilies of submodular functions - namely monotone, symmetric, and posimodular and show the following results:
1) The approximation factor of their algorithm for monotone submodular k-partition is 4/3. This result improves on the 2-factor that was known to be achievable for monotone submodular k-partition via other algorithms. Moreover, our upper bound of 4/3 matches the recently shown lower bound under polynomial number of function evaluation queries [Santiago, 2021]. Our upper bound of 4/3 is also the first improvement beyond 2 for a certain graph partitioning problem that is a special case of monotone submodular k-partition.
2) The approximation factor of their algorithm for symmetric submodular k-partition is 2. This result generalizes their approximation factor analysis beyond graph cut functions.
3) The approximation factor of their algorithm for posimodular submodular k-partition is 2. We also construct an example to show that the approximation factor of their algorithm for arbitrary submodular functions is Ω(n/k)
_p-Norm Multiway Cut
No full textWe introduce and study _p-norm-multiway-cut: the input here is an undirected graph with non-negative edge weights along with k terminals and the goal is to find a partition of the vertex set into k parts each containing exactly one terminal so as to minimize the _p-norm of the cut values of the parts. This is a unified generalization of min-sum multiway cut (when p = 1) and min-max multiway cut (when p = ∞), both of which are well-studied classic problems in the graph partitioning literature. We show that _p-norm-multiway-cut is NP-hard for constant number of terminals and is NP-hard in planar graphs. On the algorithmic side, we design an O(log² n)-approximation for all p ≥ 1. We also show an integrality gap of Ω(k^{1-1/p}) for a natural convex program and an O(k^{1-1/p-ε})-inapproximability for any constant ε > 0 assuming the small set expansion hypothesis
FIGURES 109–112, 114–116 in On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini)
No full textFIGURES 109–112, 114–116. Genitalia of Euochin nanjiabawa sp. nov.. 113. Detail of embolus of the topotype male of Euochin subwanyan (Wang & Li, 2020). 109–111. Left male palp of holotype, in prolateral (109), ventral (110) and retrolateral (111) view; 112. Detail of embolus; 114–116. Epigyne of paratype, in ventral (115) and dorsal (116) view.Published as part of Wang, Weihang & Zhang, Junxia, 2023, On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini), pp. 337-379 in Zootaxa 5297 (3) on page 361, DOI: 10.11646/zootaxa.5297.3.2, http://zenodo.org/record/800502
FIGURES 80–84 in On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini)
No full textFIGURES 80–84. Genitalia of Euochin lingyi sp. nov.. 80–82. Left male palp of holotype, in prolateral (80), ventral (81) and retrolateral (82) view; 83–84. Epigyne of paratype, in ventral (83) and dorsal (84) view.Published as part of Wang, Weihang & Zhang, Junxia, 2023, On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini), pp. 337-379 in Zootaxa 5297 (3) on page 355, DOI: 10.11646/zootaxa.5297.3.2, http://zenodo.org/record/800502
FIGURES 31–34 in On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini)
No full textFIGURES 31–34. Genitalia of Euochin buziji sp. nov.. 31. Left male palp of holotype, in ventral view; 32. RTA, in retrolateral view; 33–34. Epigyne of paratype, in ventral (33) and dorsal (34) view.Published as part of Wang, Weihang & Zhang, Junxia, 2023, On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini), pp. 337-379 in Zootaxa 5297 (3) on page 345, DOI: 10.11646/zootaxa.5297.3.2, http://zenodo.org/record/800502
FIGURES 60–66 in On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini)
No full textFIGURES 60–66. Genitalia of Euochin extraculum sp. nov.. 60–62. Left male palp of holotype, in prolateral (60), ventral (61) and retrolateral (62) view; 63. Inflated bulb; 64. Detail of embolus (© Kun Yu); 65–66. Epigyne, in ventral (65) and dorsal (66) view.Published as part of Wang, Weihang & Zhang, Junxia, 2023, On fourteen species of Euochin Prószyński, 2018 from China (Araneae: Salticidae: Euophryini), pp. 337-379 in Zootaxa 5297 (3) on page 351, DOI: 10.11646/zootaxa.5297.3.2, http://zenodo.org/record/800502
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