Elementary Number Theory with Python

PyCon mini Hiroshima 2019

1. Python Ͱָ͠Ήॳ౳੔਺࿦ Hayao Suzuki PyCon mini Hiroshima 2019 October 12, 2019
2. Contents 1 ࣗݾ঺հ 2 ॳ౳੔਺࿦ͱ͸ 3 ϐλΰϥε਺ 4 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ 5 ·ͱΊ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 2 / 39
3. ࣗݾ঺հ ͓લ୭Α ໊લ Hayao Suzukiʢླ໦ɹॣʣ Twitter @CardinalXaro ϒϩά https://xaro.hatenablog.jp/ ઐ໳ ਺ֶ (૊߹ͤ࿦ɾάϥϑཧ࿦) ֶҐ म࢜ʢ޻ֶʣ ɺిؾ௨৴େֶ ࢓ࣄ גࣜձࣾΞΠϦοδͰ Python ϓϩάϥϚΛ͍ͯ͠Δ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 3 / 39
4. ࣗݾ঺հ ٕज़ॻͷࠪಡ › ʰEffective Pythonʱ ʢΦϥΠϦʔδϟύϯʣ › ʰNumPy ʹΑΔσʔλ෼ੳೖ໳ʱ ʢΦϥΠϦʔδϟύϯʣͳͲ › https://xaro.hatenablog.jp/ ʹҰཡ͋Γ·͢ɻ ͍ΖΜͳൃද › ʮSymPy ʹΑΔ਺ࣜॲཧʯ ʢPyCon JP 2018ʣͳͲ › https://xaro.hatenablog.jp/ ʹҰཡ͋Γ·͢ɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 4 / 39
5. ॳ౳੔਺࿦ͱ͸ ੔਺࿦ͱ͸ ਺ͷੑ࣭ʹؔ͢Δ਺ֶͷҰ෼໺ ॳ౳੔਺࿦ͱ͸ ୅਺తͳख๏΍ղੳతͳख๏Λ࢖Θͳ͍਺࿦ ॳ౳͔ͩΒ؆୯Ͱ͢Ͷʁ Α͔ͬͨʂ ॳ౳ͱ͸ಛผͳ༧උ஌͕͍ࣝΒͳ͍͜ͱɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 5 / 39
6. ࠓ೔ͷൃද ͳͥ Python Λ࢖͏ͷ͔ › ൺֱతૉ௚ʹϓϩάϥϛϯάͰ͖Δ › ඪ४ϥΠϒϥϦ΋֎෦ϥΠϒϥϦ΋๛෋ʹ͋Δ › Guido van Rossum ࢯ͸ΞϜεςϧμϜେֶͰ਺ֶͱܭࢉػՊֶΛ ઐ߈͍ͯͨ͠ ࠓճ࢖͏΋ͷ › Python 3.7.x › SymPyʢه߸ܭࢉϥΠϒϥϦɺ਺࿦ϥΠϒϥϦ΋๛෋ʣ › Silvermanʰ͸͡Ίͯͷ਺࿦ ݪஶୈ 3 ൛ʱ ʢؙળग़൛ʣ ʢωλݩʣ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 6 / 39
7. ࠓ೔ͷൃද Python Ͱָ͠Ήॳ౳੔਺࿦ › ఆཧͷ݁ՌΛ Python Ͱϓϩάϥϛϯάͯ͠ΈΑ͏ › ఆཧͷূ໌͔Β Python Ͱϓϩάϥϛϯάͯ͠ΈΑ͏ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 7 / 39
8. Python Ͱָ͠Ήॳ౳੔਺࿦ ఆཧͷ݁ՌΛ Python Ͱϓϩάϥϛϯ άͯ͠ΈΑ͏ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 8 / 39
9. ϐλΰϥε਺ ఆٛ (ϐλΰϥε਺) a2 + b2 = c2 ͕੒Γཱͭࣗવ਺ͷ૊ (a; b; c) Λϐλΰϥε਺ͱݺͿɻ ໨ඪ ϐλΰϥε਺Λॏෳͳ͘ɺ΋Εͳ͘ܭࢉ͍ͨ͠ɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 9 / 39
10. ϐλΰϥε਺Λܭࢉ͠Α͏ɿࠜੑฤ ࠜੑͰܭࢉͩʂ from itertools import product for a, b, c in product(range(1, 20), repeat=3): if a ** 2 + b ** 2 == c ** 2: print(a, b, c) Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 10 / 39
11. ϐλΰϥε਺Λܭࢉ͠Α͏ɿࠜੑฤ ࠜੑͰܭࢉͨͧ͠ʂ 3 4 5 4 3 5 5 12 13 6 8 10 8 6 10 8 15 17 9 12 15 12 5 13 12 9 15 15 8 17 ॏෳ͕ͨ͘͞Μ͋Δ͠ɺ΋Ε͕͋Δ͔΋͠Εͳ͍ɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 11 / 39
12. ط໿ϐλΰϥε਺ ఆٛ (ط໿ϐλΰϥε਺) ޓ͍ʹૉͰ͋Δϐλΰϥε਺Λط໿ϐλΰϥε਺ͱݺͿɻ ط໿ϐλΰϥε਺͚ͩΛੜ੒͢Ε͹ଞͷϐλΰϥε਺͸ੜ੒Ͱ͖Δɻ ϐλΰϥε਺ (3; 4; 5) ͔Βผͷϐλΰϥε਺ (6; 8; 10) Λ࡞Δ͜ͱ͕Ͱ ͖Δɻ ࣍ͳΔ໨ඪ ط໿ϐλΰϥε਺Λॏෳͳ͘ɺ΋Εͳ͘ܭࢉ͍ͨ͠ɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 12 / 39
13. ط໿ϐλΰϥε਺Λܭࢉ͠Α͏ ͪΐͬͱ޻෉ͨ͠ from itertools import combinations from math import gcd for a, b, c in combinations(range(1, 50), 3): if a ** 2 + b ** 2 == c ** 2 and gcd(a, b) == 1: print(a, b, c) ͪΐͬͱ޻෉ͨ͠ › a; b; c ͸ͦΕͧΕҧ͏਺Ͱ͋Δ › a; b ͸ޓ͍ʹૉͰ͋Δ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 13 / 39
14. ط໿ϐλΰϥε਺Λܭࢉ͠Α͏ ط໿ϐλΰϥε਺ͷܭࢉ 3 4 5 5 12 13 7 24 25 8 15 17 9 40 41 12 35 37 20 21 29 ॏෳ͸ͳͦ͞͏͕ͩɺ΋Ε͕͋Δ͔΋͠Εͳ͍...ɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 14 / 39
15. ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉ͠Α͏ ໋୊ ط໿ϐλΰϥε਺ (a; b; c) ͸ޓ͍ʹૉͳح਺ s; t(s > t) Λ༻͍ͯ a = st; b = s2 ` t2 2 ; c = s2 + t2 2 ͱͰ͖Δɻ ͭ·Γ... ޓ͍ʹૉͳح਺ͷϖΞ (s; t) ͕ط໿ϐλΰϥε਺ (a; b; c) ʹରԠ͢Δɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 15 / 39
16. ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉ͠Α͏ ิ୊ (͋ͱͰͬ͘͡Γಡ΋͏) ط໿ϐλΰϥε਺ (a; b; c) ͷ a; b ͷҰํ͸ۮ਺Ͱ΋͏Ұํ͸ح਺Ͱ͋Δɻ ·ͨɺc ͸ৗʹح਺Ͱ͋Δɻ ূ໌ʢ͋ͱͰͬ͘͡Γಡ΋͏ʣ. ࣗવ਺ͷ૊ (a; b; c) Λط໿ϐλΰϥε਺ͱ͢Δɻ ·ͣɺa; b ͕ڞʹۮ਺ͳΒ͹ɺϐλΰϥε਺ͷఆ͔ٛΒ c ΋ۮ਺ͱͳΓɺ (a; b; c) ͸ڞ௨Ҽ਺ 2 Λ࣋ͭ͜ͱʹͳΓԾఆʹ൓͢Δɻ࣍ʹɺa; b ͕ڞ ʹح਺ͳΒ͹ɺϐλΰϥε਺ͷఆ͔ٛΒ c ͸ۮ਺ͱͳΔɻ͜ͷͱ͖ɺ a = 2x + 1; b = 2y + 1; c = 2z ͱ͢Δͱ a2 + b2 = c2 ) 2(x2 + x + y2 + y) + 1 = 2z2 ͱͳΓໃ६ɻ Αͬͯɺa; b ͷ಺ɺҰํ͸ۮ਺Ͱ΋͏Ұํ͸ح਺Ͱ͋Δɻ·ͨɺϐλΰϥ ε਺ͷఆ͔ٛΒ c ͸ح਺ͱͳΔɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 16 / 39
17. ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉ͠Α͏ ิ୊ (͋ͱͰͬ͘͡Γಡ΋͏) ط໿ϐλΰϥε਺ (a; b; c) ʹ͓͍ͯɺa Λح਺ɺb Λۮ਺ͱ͢Δɻ͜ͷͱ ͖ɺ(c ` b)(c + b) ͸ޓ͍ʹૉͰ͋Δɻ ূ໌ʢ͋ͱͰͬ͘͡Γಡ΋͏ʣ. ࣗવ਺ͷ૊ (a; b; c) Λط໿ϐλΰϥε਺ͱ͠ɺa Λح਺ɺb Λۮ਺ͱ͢ ΔɻԾఆ͔Βɺa2 = c2 ` b2 = (c ` b)(c + b) ͱͰ͖Δɻ c ` b; c + b ͷڞ௨Ҽ਺Λ d ͱ͢Δͱɺd ͸ (c + b) + (c ` b) = 2c; (c + b) ` (c ` b) = 2b ΋ׂΓ੾ΔɻԾఆ ͔Β b; c ͸ط໿ͳͷͰ d ͸ 1 ·ͨ͸ 2 Ͱ͋Δɻ͔͠͠ɺ (c ` b)(c + b) = a2 Ͱ͋Γɺa ͸ح਺ͳͷͰ d ͸ 1 ʹଞͳΒͳ͍ɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 17 / 39
18. ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉ͠Α͏ ิ୊ (͋ͱͰͬ͘͡Γಡ΋͏) ط໿ϐλΰϥε਺ (a; b; c) ʹ͓͍ͯɺa Λح਺ɺb Λۮ਺ͱ͢Δɻ͜ͷͱ ͖ɺc ` b; c + b ͸ͦΕͧΕฏํ਺ͱͳΔɻ ূ໌ʢ͋ͱͰͬ͘͡Γಡ΋͏ʣ. ࣗવ਺ͷ૊ (a; b; c) Λط໿ϐλΰϥε਺ͱ͠ɺa Λح਺ɺb Λۮ਺ͱ͢Δɻ Ծఆ͔Βɺa2 = c2 ` b2 = (c ` b)(c + b) ͱͰ͖Δɻc ` b; c + b ͸ ޓ͍ʹૉͰ͋Γɺ͔ͭ (c ` b)(c + b) = a2 ͳͷͰɺ(c ` b)(c + b) ͸ ฏํ਺ͱͳΔɻΑͬͯɺc ` b; c + b ͕ͦΕͧΕฏํ਺ͱͳΔɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 18 / 39
19. ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉ͠Α͏ ໋୊ ط໿ϐλΰϥε਺ (a; b; c) ͸ޓ͍ʹૉͳح਺ s; t(s > t) Λ༻͍ͯ a = st; b = s2 ` t2 2 ; c = s2 + t2 2 ͱͰ͖Δɻ ূ໌ʢ͋ͱͰͬ͘͡Γಡ΋͏ʣ. ࣗવ਺ͷ૊ (a; b; c) Λط໿ϐλΰϥε਺ͱ͠ɺa Λح਺ɺb Λۮ਺ͱ͢Δɻ Ծఆ͔Βɺa2 = c2 ` b2 = (c ` b)(c + b) ͱͰ͖Δɻc ` b; c + b ͸ ͦΕͧΕฏํ਺ͳͷͰɺc + b = s2; c ` b = t2 ͱͰ͖ΔɻΑͬͯɺ c = s2 + t2 2 ; b = s2 ` t2 2 ͱͳΔɻ·ͨɺ a = q(c ` b)(c + b) = st ͱͳΔɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 19 / 39
20. ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉ͠Α͏ ্ख͘޻෉ͨ͠ from itertools import combinations from math import gcd for t, s in filter( lambda x: gcd(*x) == 1, combinations(range(1, 10, 2), r=2), ): print( s * t, (s ** 2 - t ** 2) // 2, (s ** 2 + t ** 2) // 2, ) Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 20 / 39
21. ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉ͠Α͏ ط໿ϐλΰϥε਺Λ΋ͬͱ্ख͘ܭࢉͨ͠ 3 4 5 5 12 13 7 24 25 9 40 41 15 8 17 21 20 29 35 12 37 45 28 53 63 16 65 ॏෳͳ͘ɺ΋Εͳ͘ܭࢉͰ͖ͨʂ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 21 / 39
22. Python Ͱָ͠Ήॳ౳੔਺࿦ ఆཧͷ݁ՌΛ Python Ͱϓϩάϥϛϯάͯ͠ΈΑ͏ › ݁ՌΛͦͷ··࣮૷ͯ͠۩ମྫΛ؍࡯͢Δ › ҙ֎ͳ๏ଇ͕ݟ͔ͭΔʢ͔΋ʣ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 22 / 39
23. Python Ͱָ͠Ήॳ౳੔਺࿦ ఆཧͷূ໌͔Β Python Ͱϓϩάϥϛ ϯάͯ͠ΈΑ͏ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 23 / 39
24. 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ ఆٛ (੔਺ͷ߹ಉ) ੔਺ a; b ͓Αͼ m ʹ͓͍ͯɺa ` b ͕ m ͷഒ਺ͱͳΔͱ͖ɺa; b ͸Λ m Λ๏ͱͯ͠߹ಉͱݺͼɺa ” b (mod m) ͱද͢ɻ ఆཧ (Fermat ͷ 2 ฏํ࿨ఆཧ) حૉ਺ p ͕ 2 ͭͷฏํ਺ͷ࿨ͰදͤΔ͜ͱͷඞཁे෼৚݅͸ p ” 1 (mod 4) Ͱ͋Δɻ 2 ͭͷฏํ਺ͷ࿨ͰදͤΔʁ p = 97 Λྫʹߟ͑Δɻ › 97 = 92 + 42 ͱͰ͖ΔͷͰɺ97 ” 1 (mod 4) Ͱ͋Δɻ ʢ؆୯ʣ › 97 ” 1 (mod 4) Ͱ͋ΔͷͰɺ97 = 92 + 42 ͱͰ͖Δɻ ʢෆࢥٞʣ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 24 / 39
25. 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ ূ໌ (p = x2 + y2 ) p ” 1 (mod 4)). حૉ਺ p ͕ 2 ͭͷฏํ਺ͷ࿨ͰදͤΔͳΒ͹ɺp = x2 + y2 ͱͳΔɻp ͸ح਺ͳͷͰɺx Λۮ਺ɺy Λح਺ͱͯ͠Α͍ɻ͜ͷͱ͖ɺ x = 2m; y = 2n + 1 ͱ͢Δͱ p = x2 + y2 = (2m)2 + (2n + 1)2 = 4(m2 + n2 + n) + 1 ΑΓɺp ͸ 4 Λ๏ͱͯ͠ 1 ͱ߹ಉͰ͋Δɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 25 / 39
26. ূ໌ͷϥϑεέον େࡶ೺ͳํ਑ › ͍͖ͳΓ x2 + y2 = p Λຬͨ͢ (x; y) Λ౰ͯΔͷ͸೉͍͠ɻ › x2 + y2 = Mp Λຬͨ͢ (x; y; M) ͸ൺֱత؆୯ʹग़ͤΔͷͰ ग़͢ɻ › M ͷ஋ΛͲΜͲΜݮΒͯ͠ 1 ʹ͢Δɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 26 / 39
27. ূ໌ͷεέον ূ໌ (p ” 1 (mod 4) ) p = x2 + y2) ͷεέον 1 p Λ 4 Λ๏ͱͯ͠ 1 ͱ߹ಉͳૉ਺ͱ͢Δɻ 2 A2 + B2 = Mp ͳΔ (A; B; M) Λ୳͢ɻM = 1 ͳΒऴྃɻ 3 (A; B; M) ͔Β a2 + b2 = Mr; r » M ` 1 ͳΔ (a; b; r) Λ ಘΔɻ 4 A2 + B2 = Mp; a2 + b2 = Mr ͔Β u2 + v2 = rp ΛಘΔɻ 5 A u; B v; M r ͱͯ͠ 2 ʹ໭Δɻ ͜ΕΛແݶ߱Լ๏ͱݺͿɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 27 / 39
28. ূ໌ͷεέον ิ୊ ߹ಉํఔࣜ x2 ” `1 (mod p) ͸ղΛ࣋ͭɻ ূ໌ʢఱԼΓʣ. ฏํ৒༨ͷ૬ޓ๏ଇ͔Βಋ͚Δɻ ͍͍ײ͡ʹ A2 + B2 = Mp ͳΔ (A; B; M) Λ୳͢ ߹ಉํఔࣜ x2 ” `1 (mod p) ͷղΛ A ͱ͠ɺB = 1 ͱ͢Δͱɺ A2 + B2 ͸ p ͷഒ਺Ͱ͋Δɻ·ͨɺM = A2 + B2 p ͱͳΔɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 28 / 39
29. A2 + B2 = Mp ͳΔ (A; B; M) Λ୳͢ ߹ಉํఔࣜ x2 ” `1 (mod p) ͷղΛࢉग़͢ΔʢఱԼΓʣ from random import randint from sympy.ntheory import isprime, legendre_symbol def solve_quadratic(p): if not (isprime(p) and p % 4 == 1): raise ValueError while True: a = randint(1, p - 1) b = pow(a, (p - 1) // 4, p) if legendre_symbol(a, p) == -1 and 1 <= b < p: return b Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 29 / 39
30. A2 + B2 = Mp ͳΔ (A; B; M) Λ୳͢ (A; B; M) Λ୳͢ def sums_of_two_squares(p): """4 Λ๏ͱͯ͠ 1 ͱ߹ಉͳૉ਺Λ 2 ͭͷฏํ਺ͷ࿨Ͱද͢""" if not (isprime(p) and p % 4 == 1): raise ValueError A, B = solve_quadratic(p), 1 M = divmod(A ** 2 + B ** 2, p)[0] Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 30 / 39
31. a2 + b2 = Mr Λ୳͢ a2 + b2 = Mr Λ୳͢ ҎԼͷ৚݅Λຬͨ͢Α͏ʹ a; b ΛબͿɻ a ” A (mod M) b ” B (mod M) ` 1 2 M » a; b » 1 2 M r ͱ M ͷؔ܎ͷൿີ r = a2 + b2 M » “ M 2 ”2 + “M 2 ”2 M = M 2 < M: Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 31 / 39
32. a2 + b2 = Mr Λ୳͢ a2 + b2 = Mr Λ୳͢ from sympy.ntheory.modular import solve_congruence def sums_of_two_squares(p): """4 Λ๏ͱͯ͠ 1 ͱ߹ಉͳૉ਺Λ 2 ͭͷฏํ਺ͷ࿨Ͱද͢""" if not (isprime(p) and p % 4 == 1): raise ValueError A, B = solve_quadratic(p), 1 M = divmod(A ** 2 + B ** 2, p)[0] a = solve_congruence((A, M), symmetric=True)[0] b = solve_congruence((B, M), symmetric=True)[0] r = divmod(a ** 2 + b ** 2, M)[0] Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 32 / 39
33. ূ໌ͷεέον ิ୊ (u2 + v2)(A2 + B2) = (uA + vB)2 + (vA ` uB)2 ূ໌. ܭࢉ͢Δ͚ͩɻ (uA + vB)2 + (vA ` uB)2 = (u2A2 + 2uAvB + v2B2) + (v2A2 ` 2vAuB + u2B2) = u2A2 + v2B2 + v2A2 + u2B2 = (u2 + v2)(A2 + B2): Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 33 / 39
34. ૯࢓্͛ 2 ͭͷํఔࣜ A2 + B2 = Mp a2 + b2 = Mr 2 ͭͷํఔࣜͷؔ܎ (a2 + b2)(A2 + B2) = M2rp )(aA + bB)2 + (bA ` aB)2 = M2rp ) aA + bB M !2 + bA ` aB M !2 = rp r » M 2 ͳͷͰɺޮ཰Α͘ܭࢉͰ͖Δɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 34 / 39
35. 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ def sums_of_two_squares(p): A, B = solve_quadratic(p), 1 M = divmod(A ** 2 + B ** 2, p)[0] while True: a = solve_congruence((A, M), symmetric=True)[0] b = solve_congruence((B, M), symmetric=True)[0] r = divmod(u ** 2 + v ** 2, M)[0] s = abs((a * A + b * B) // M) t = abs((b * A - a * B) // M) if r == 1: print(f"${s}^2 + {t}^2={p}$") return else: A, B, M = s, t, r Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 35 / 39
36. 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ from sympy import primerange primes_1_mod_4 = ( p for p in primerange(1, 100) if p % 4 == 1 ) for p in primes_1_mod_4: sums_of_two_squares(p) Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 36 / 39
37. 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ 2 ͭͷฏํ਺ͷ࿨ͰදͤΔૉ਺ 22 + 12 = 5 32 + 22 = 13 42 + 12 = 17 52 + 22 = 29 62 + 12 = 37 52 + 42 = 41 72 + 22 = 53 62 + 52 = 61 82 + 32 = 73 82 + 52 = 89 92 + 42 = 97 Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 37 / 39
38. Python Ͱָ͠Ήॳ౳੔਺࿦ ఆཧͷূ໌͔Β Python Ͱϓϩάϥϛϯάͯ͠ΈΑ͏ › ߏ੒తͳূ໌͸ϓϩάϥϛϯάͰ͖Δʢ͜ͱ΋͋Δʣ › ϓϩάϥϛϯάͰ͖Ε͹ূ໌ΛཧղͰ͖Δʢ͔΋͠Εͳ͍ʣ શମ૾Λݟ͍ͨ... ϓϩάϥϜશମ͸ https://github.com/HayaoSuzuki/ PyCon-mini-Hiroshima-2019/blob/master/20191012note.ipynb ʹ ͋Γ·͢ɻ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 38 / 39
39. ·ͱΊ ͳͥ Python Λ࢖͏ͷ͔ › ൺֱతૉ௚ʹϓϩάϥϛϯάͰ͖Δ › ඪ४ϥΠϒϥϦ΋֎෦ϥΠϒϥϦ΋๛෋ʹ͋Δ › ࠔͬͨΒ SymPy Λ౰ͨΕ͹ղܾ͢Δ͜ͱ͕ଟ͍ ఆཧͷ݁ՌΛ Python Ͱϓϩάϥϛϯάͯ͠ΈΑ͏ › ݁ՌΛͦͷ··࣮૷ͯ͠۩ମྫΛ؍࡯͢Δ › ҙ֎ͳ๏ଇ͕ݟ͔ͭΔʢ͔΋ʣ ఆཧͷূ໌͔Β Python Ͱϓϩάϥϛϯάͯ͠ΈΑ͏ › ߏ੒తͳূ໌͸ϓϩάϥϛϯάͰ͖Δʢ͜ͱ΋͋Δʣ › ϓϩάϥϛϯάͰ͖Ε͹ূ໌ΛཧղͰ͖Δʢ͔΋͠Εͳ͍ʣ Hayao (Hiroshima 2019) Number Theory with Python October 12, 2019 39 / 39