Rotationally symmetric tilings with convex pentagons belonging to both the Type 1 and Type 7

Rotationally symmetric tilings by a convex pentagonal tile belonging to both the Type 1 and Type 7 families are introduced. Among them are spiral tilings with two- and four-fold rotational symmetry. Those rotationally symmetric tilings are connected edge-to-edge and have no axis of reflection symmetry.Comment: 13 pages, 16 figures. arXiv admin note: text overlap with arXiv:2005.08470, arXiv:2005.1270

Anomaly Cancellations in the Type I D9-anti-D9 System and the USp(32) String Theory

We check some consistency conditions for the D9-anti-D9 system in type I string theory. The gravitational anomaly and gauge anomaly for SO(n) x SO(m) gauge symmetry are shown to be cancelled when n-m=32. In addition, we find that a string theory with USp(n) x USp(m) gauge symmetry also satisfies the anomaly cancellation conditions. After tachyon condensation, the theory reduces to a tachyon-free USp(32) string theory, though there is no spacetime supersymmetry.Comment: 17 pages + 10 eps figures, LaTeX; minor corrections, reference added, version to appear in Prog. Theor. Phy

Comments on Duality in MQCD

We clarify some ambiguous points in a derivation of duality via brane exchange using M-theory language, and propose a ``proof'' of duality in MQCD. Actually, duality in MQCD is rather trivial and does not need a complicated proof. The problem is how to interpret it in field theory language. We examine BPS states in N=2 theory and find the particle correspondence under duality. In the process, we also find some exotic particles in N=2 MQCD, and we observe an interesting phenomenon in type IIA string theory, namely, that fundamental strings are converted into D2-branes via the exchange of two NS5-branes. We also discuss how we should understand Seiberg's N=1 duality from exact duality in MQCD.Comment: 29 pages + 20 uuencoded eps figures, LaTeX with PTPTeXsty, typo corrected, version to appear in Prog. Theor. Phy

The sharp energy-capacity inequality on convex symplectic manifolds

In symplectic geometry, symplectic invariants are useful tools in studying symplectic phenomena. Hofer-Zehnder capacity and displacement energy are important symplectic invariants. Usher proved the so-called sharp energy-capacity inequality between Hofer-Zehnder capacity and the displacement energy for closed symplectic manifolds. In this paper, we extend the sharp energy-capacity inequality to convex symplectic manifolds

Convex pentagons and convex hexagons that can form rotationally symmetric tilings

In this study, the properties of convex hexagons that can generate rotationally symmetric edge-to-edge tilings are discussed. Since the convex hexagons are equilateral convex parallelohexagons, convex pentagons generated by bisecting the hexagons can form rotationally symmetric non-edge-to-edge tilings. In addition, under certain circumstances, tiling-like patterns with an equilateral convex polygonal hole at the center can be formed using these convex hexagons or pentagons.Comment: 23 pages, 28 figures. arXiv admin note: text overlap with arXiv:2005.0847