def _omega_pm_spectrum_odd_c(n: int, field: 'Field', sign: int) -> Iterable[int]: """Spectra of Omega^e_{2n}(q) for odd q. Based on [1, Corollary 8] and [3, Lemma 2.3] Point 3 of [1, Corollary 8] contains an error that was corrected in [3, Lemma 2.3] """ n //= 2 q = field.order p = field.char def nk(k): return (p ** (k - 1) + 3) // 2 # (1) a1 = [(q ** n - sign) // 2] # (2) a2 = SemisimpleElements(q, n, min_length=2, parity=sign) # (3) a3 = [] k = 1 while True: n_k = nk(k) if n_k >= n: break for delta in [1, -1]: dk = gcd(4, q ** n_k - sign * delta) // 2 a3.append( p ** k * lcm( dk, (q**(n - n_k) - delta) // dk ) ) k += 1 # (4) a4 = MixedElements(q, n, nk, lambda k: p ** k, min_length=2) # (5) a5 = [] for elem in SemisimpleElements(q, n - 2, min_length=2, parity=sign): a5.append(elem.lcm(SpectraElement(p, q, [1], [-1]))) a5.append(elem.lcm(SpectraElement(p, q, [1], [1]))) # (6) t = (q ** (n - 2) - sign) // 2 a6 = [p * lcm(q - 1, t), p * lcm(q + 1, t)] # (7) k = numeric.get_exponent(2 * n - 3, p) a7 = [] if k is None else [p * (2 * n - 3) * gcd(4, q ** n - sign) // 2] # (8) a8 = [p * (q * q - 1), p * (q * q + 1)] if n == 4 and sign == 1 else [] # (9) a9 = [9 * (q - 1), 9 * (q + 1)] if n == 4 and p == 3 and sign == 1 else [] return itertools.chain(a1, a2, a3, a4, a5, a6, a7, a8, a9)
def spectrum(n, field): n //= 2 q = field.order p = field.char # if gcd(4, q^n-e) != 4, then POmega = Omega b = (q % 4 == 3 and n % 2 == 1) if e == -1 else ( q % 4 == 1) # true iff gcd(4, q^n-e)=4 if not b: return _omega_pm_spectrum(e)(n * 2, field) nk = lambda k: (p**(k - 1) + 3) // 2 # (1) a1 = [(q**n - sign) // 4] # (2) a2 = [] for n1 in xrange(1, n): for e1 in [-1, 1]: a = q**n1 - e1 b = q**(n - n1) - e * e1 d = 2 if _equal_two_part(a, b) else 1 a2.append(lcm(a, b) // d) # (3) a3 = SemisimpleElements(q, n, min_length=3, parity=sign) # (4) a4 = [] k = 1 while True: n_k = nk(k) if n_k >= n: break a4.append(p**k * (q**(n - n_k) + 1) // 2) a4.append(p**k * (q**(n - n_k) - 1) // 2) k += 1 # (5) a5 = MixedElements(q, n, nk, lambda k: p**k, min_length=2) # (6) a6 = [] for elem in SemisimpleElements(q, n - 2, min_length=2, parity=sign): a6.append(elem.lcm(SpectraElement(p, q, [1], [-1]))) a6.append(elem.lcm(SpectraElement(p, q, [1], [1]))) # (7) t = (q**(n - 2) - sign) // 2 a7 = [p * lcm(q - 1, t), p * lcm(q + 1, t)] # (8) k = numeric.get_exponent(2 * n - 3, p) a8 = [] if k is None else [p * (2 * n - 3)] return itertools.chain(a1, a2, a3, a4, a5, a6, a7, a8)
def _omega_pm_spectrum_odd_c(n, field, sign): """Spectra of Omega^e_{2n}(q) for odd q. [1, Corollary 8] """ n //= 2 q = field.order p = field.char nk = lambda k: (p**(k - 1) + 3) // 2 # (1) a1 = [(q**n - sign) // 2] # (2) a2 = SemisimpleElements(q, n, min_length=2, parity=sign) # (3) a3 = [] k = 1 while True: n_k = nk(k) if n_k >= n: break dk = gcd(4, q**n_k - sign) // 2 a3.append(p**k * lcm(dk, (q**(n - n_k) + 1) // dk)) a3.append(p**k * lcm(dk, (q**(n - n_k) - 1) // dk)) k += 1 # (4) a4 = MixedElements(q, n, nk, lambda k: p**k, min_length=2) # (5) a5 = [] for elem in SemisimpleElements(q, n - 2, min_length=2, parity=sign): a5.append(elem.lcm(SpectraElement(p, q, [1], [-1]))) a5.append(elem.lcm(SpectraElement(p, q, [1], [1]))) # (6) t = (q**(n - 2) - sign) // 2 a6 = [p * lcm(q - 1, t), p * lcm(q + 1, t)] # (7) k = numeric.get_exponent(2 * n - 3, p) a7 = [] if k is None else [p * (2 * n - 3) * gcd(4, q**n - sign) // 2] # (8) a8 = [p * (q * q - 1), p * (q * q + 1)] if n == 4 and sign == 1 else [] # (9) a9 = [9 * (q - 1), 9 * (q + 1)] if n == 4 and p == 3 and sign == 1 else [] return itertools.chain(a1, a2, a3, a4, a5, a6, a7, a8, a9)
def _omega_pm_spectrum_even_c(n: int, field: 'Field', sign: int) -> Iterable[int]: """Spectra for groups \Omega^{\pm}(2^k). [1, Corollary 4] """ n //= 2 q = field.order # (1) a1 = SemisimpleElements(q, n, parity=sign) # (2) a2 = MixedElements(q, n, lambda k: 2 ** (k - 1) + 2, lambda k: 2 ** (k + 1)) # (3) a3 = (2 * elem for elem in SemisimpleElements(q, n - 2)) # (4) a4 = [] for elem in SemisimpleElements(q, n - 2, parity=sign): a4.append(2 * lcm(q - 1, elem)) a4.append(2 * lcm(q + 1, elem)) # (5) a5 = [] signMod = 0 if sign == 1 else 1 for ni in FullBoundedSets(n - 3): if len(ni) % 2 != signMod: continue a5.append(4 * SpectraElement(q=q, partition=[1] + ni, signs=[-1] + [1] * len(ni))) # (6) a6 = (elem.lcm(SpectraElement(4, q, [1], [1])) for elem in SemisimpleElements(q, n - 3, parity=-sign)) # (7) k = numeric.get_exponent(n - 2, 2) a7 = [] if k is None else [4 * (n - 2)] return itertools.chain(a1, a2, a3, a4, a5, a6, a7)
def spectrum(n, field): n //= 2 q = field.order p = field.char # (1) a1 = SemisimpleElements(q, n, parity=e) # (2) a2 = MixedElements(q, n, lambda k: (p**(k - 1) + 3) // 2, lambda k: p**k) # (3) a3 = [] for elem in SemisimpleElements(q, n - 2, parity=e): a3.append(elem.lcm(SpectraElement(p, q, [1], [-1]))) a3.append(elem.lcm(SpectraElement(p, q, [1], [1]))) # (4) k = numeric.get_exponent(2 * n - 3, p) a4 = [] if k is None else [2 * p * (2 * n - 3)] return itertools.chain(a1, a2, a3, a4)
def test_lcm(self): elem1 = SpectraElement(q=2, partition=[2, 3], signs=[1, -1]) elem2 = SpectraElement(q=2, partition=[3, 4], signs=[1, -1]) expected = "[2^4 - 1, 2^3 + 1, 2^3 - 1, 2^2 + 1]" self.assertEqual(expected, elem1.lcm(elem2).str_verbose())
def test_str(self): elem = SpectraElement(3, 2, [2, 3, 4], [1, -1, 1]) expected = "3 * [2^4 + 1, 2^3 - 1, 2^2 + 1]" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(3) self.assertEqual("3", elem.str_verbose()) elem = SpectraElement(q=2, partition=[2, 3, 4], signs=[1, -1, 1]) expected = "[2^4 + 1, 2^3 - 1, 2^2 + 1]" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(q=2, partition=[1, 1, 4], signs=[1, -1, 1]) expected = "[2^4 + 1, 2 + 1, 2 - 1]" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(q=2, partition=[1], signs=[1]) expected = "2 + 1" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(quotient=2, q=2, partition=[1], signs=[1]) expected = "2 * (2 + 1)" self.assertEqual(expected, elem.str_verbose())
def test_mult(self): elem = SpectraElement(q=2, partition=[2, 3], signs=[1, -1]) expected = "2 * [2^3 - 1, 2^2 + 1]" self.assertEqual(expected, (elem * 2).str_verbose())
def test_lcm(self): elem1 = SpectraElement(q=2, partition=[2, 3], signs=[1, -1]) elem2 = SpectraElement(q=2, partition=[3, 4], signs=[1, -1]) expected = "[2^2 + 1, 2^3 - 1, 2^3 + 1, 2^4 - 1]" self.assertEqual(expected, elem1.lcm(elem2).str_verbose())
def test_str(self): elem = SpectraElement(3, 2, [2, 3, 4], [1, -1, 1]) expected = "3 * [2^2 + 1, 2^3 - 1, 2^4 + 1]" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(3) self.assertEqual("3", elem.str_verbose()) elem = SpectraElement(q=2, partition=[2, 3, 4], signs=[1, -1, 1]) expected = "[2^2 + 1, 2^3 - 1, 2^4 + 1]" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(q=2, partition=[1, 1, 4], signs=[1, -1, 1]) expected = "[2 - 1, 2 + 1, 2^4 + 1]" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(q=2, partition=[1], signs=[1]) expected = "2 + 1" self.assertEqual(expected, elem.str_verbose()) elem = SpectraElement(quotient=2, q=2, partition=[1], signs=[1]) expected = "2 * (2 + 1)" self.assertEqual(expected, elem.str_verbose())