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/**************************************************************************
* *
* Regina - A Normal Surface Theory Calculator *
* Test Suite *
* *
* Copyright (c) 1999-2025, Ben Burton *
* For further details contact Ben Burton (bab@debian.org). *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; either version 2 of the *
* License, or (at your option) any later version. *
* *
* As an exception, when this program is distributed through (i) the *
* App Store by Apple Inc.; (ii) the Mac App Store by Apple Inc.; or *
* (iii) Google Play by Google Inc., then that store may impose any *
* digital rights management, device limits and/or redistribution *
* restrictions that are required by its terms of service. *
* *
* This program is distributed in the hope that it will be useful, but *
* WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see <https://www.gnu.org/licenses/>. *
* *
**************************************************************************/
#include <cmath>
#include <memory>
#include "surface/normalsurfaces.h"
#include "triangulation/example3.h"
#include "triangulation/dim3.h"
#include "testhelper.h"
using regina::Example;
using regina::NormalSurfaces;
using regina::Triangulation;
TEST(IncompressibleTest, isHaken) {
// Some non-Haken prime manifolds:
EXPECT_FALSE(Example<3>::threeSphere().isHaken());
EXPECT_FALSE(Example<3>::lens(2, 1).isHaken());
EXPECT_FALSE(Example<3>::poincare().isHaken());
// Some Haken Seifert fibred spaces and surface bundles:
Triangulation<3> sfsSphere = Triangulation<3>::fromIsoSig(
"gLALQbccefffemkbemi"); // SFS [S2: (2,1) (2,1) (2,1) (2,-1)]
Triangulation<3> sfsTorus = Triangulation<3>::fromIsoSig(
"gvLQQcdefeffnwnpkhe"); // SFS [T: (1,1)]
Triangulation<3> bundle = Triangulation<3>::fromIsoSig(
"gvLQQedfedffrwawrhh"); // T x S1
EXPECT_TRUE(sfsSphere.isHaken());
EXPECT_TRUE(sfsTorus.isHaken());
EXPECT_TRUE(bundle.isHaken());
// The Hakenness test always returns false for reducible manifolds.
EXPECT_FALSE(Example<3>::lens(0, 1).isHaken());
{
Triangulation<3> connSum(sfsSphere);
connSum.connectedSumWith(bundle);
EXPECT_FALSE(connSum.isHaken());
}
}
static bool hasIncompressibleSurface(const Triangulation<3>& tri) {
NormalSurfaces s(tri, regina::NormalCoords::Standard,
regina::NormalList::EmbeddedOnly);
for (const auto& f : s)
if (f.isIncompressible())
return true;
return false;
}
TEST(IncompressibleTest, isIncompressible) {
// Simple cases;
EXPECT_FALSE(hasIncompressibleSurface(Example<3>::threeSphere()));
// RP^3 should have no incompressible surface, since isIncompressible()
// always works with the double cover of a 1-sided surface.
EXPECT_FALSE(hasIncompressibleSurface(Example<3>::lens(2, 1)));
EXPECT_FALSE(hasIncompressibleSurface(Example<3>::layeredLoop(2, false)));
// Some other non-Haken manifolds:
EXPECT_FALSE(hasIncompressibleSurface(Example<3>::poincare()));
// Some Haken Seifert fibred spaces and surface bundles:
EXPECT_TRUE(hasIncompressibleSurface(Triangulation<3>::fromIsoSig(
"gLALQbccefffemkbemi"))); // SFS [S2: (2,1) (2,1) (2,1) (2,-1)]
EXPECT_TRUE(hasIncompressibleSurface(Triangulation<3>::fromIsoSig(
"gvLQQcdefeffnwnpkhe"))); // SFS [T: (1,1)]
EXPECT_TRUE(hasIncompressibleSurface(Triangulation<3>::fromIsoSig(
"gvLQQedfedffrwawrhh"))); // T x S1
}
TEST(IncompressibleTest, hasCompressingDisc) {
// Trivial cases:
EXPECT_FALSE(Triangulation<3>().hasCompressingDisc());
// Balls:
EXPECT_FALSE(Example<3>::ball().hasCompressingDisc());
// ... a snapped tetrahedron:
EXPECT_FALSE(Triangulation<3>::fromGluings(1, {
{ 0, 0, 0, {3,1,2,0} }}).hasCompressingDisc());
// ... a triangular pillow:
EXPECT_FALSE(Triangulation<3>::fromGluings(2, {
{ 0, 0, 1, {} },
{ 0, 1, 1, {} },
{ 0, 2, 1, {} }}).hasCompressingDisc());
// ... a 4-tetrahedron ball:
EXPECT_FALSE(Triangulation<3>::fromGluings(4, {
{ 0, 2, 0, {0,2} },
{ 0, 1, 1, {2,0,1,3} },
{ 1, 2, 2, {} },
{ 1, 1, 2, {2,0,1,3} },
{ 2, 1, 3, {2,0,1,3} },
{ 3, 2, 3, {1,2} }}).hasCompressingDisc());
// Orientable handlebodies:
EXPECT_TRUE(Example<3>::lst(1, 2).hasCompressingDisc());
EXPECT_TRUE(Example<3>::lst(3, 4).hasCompressingDisc());
EXPECT_TRUE(Triangulation<3>::fromIsoSig(
"eHucabdhs").hasCompressingDisc()); // Genus 2
EXPECT_TRUE(Triangulation<3>::fromIsoSig(
"tbLGburuGuqHbKgqGacdjmpqsrqbkltl").hasCompressingDisc()); // Genus 7
// Hyperbolic manifolds:
{
Triangulation<3> tri = Example<3>::figureEight();
tri.truncateIdeal();
tri.simplify();
EXPECT_FALSE(tri.hasCompressingDisc());
}
}
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