In this work, a five-parameter jerk system with one hyperbolic sine nonlinearity is proposed, in which ε is a small parameter, and a, b, c, d are some other parameters. For ε=0, the system is Z2 symmetric. For ε≠0, the system loses the symmetry. For the symmetrical case, the pitchfork bifurcation and Hopf bifurcation of the origin are studied analytically by Sotomayor's theorem and Hassard's formulas, respectively. These bifurcations can be either supercritical or subcritical depending on the governing parameters. In comparison, it is much more restrictive for the origin of the Lorenz system: Only a supercritical pitchfork bifurcation is available. Thus, the symmetrical system can exhibit very rich local bifurcation structures. The continuation of local bifurcations leads to the main contribution of this work, i.e., the discovery of two basic mechanisms of chaotic motions for the jerk systems. For four typical cases, Cases A–D, by varying the parameter a, the mechanisms are identified by means of bifurcation diagrams. Cases A and B are Z2 symmetric, while Cases C and D are asymmetric (caused by constant terms). The forward period-doubling routes to chaos are observed for Cases A and C; meanwhile, the backward period-doubling routes to chaos are observed for Cases B and D. The dynamical behaviors of these cases are studied via phase portraits, two-sided Poincaré sections and Lyapunov exponents. Using Power Simulation (PSIM), a circuit simulation model for a chaotic jerk system is created. The circuit simulations match the results of numerical simulations, which further validate the dynamical behavior of the jerk system.
Citation: Xiaoyan Hu, Bo Sang, Ning Wang. The chaotic mechanisms in some jerk systems[J]. AIMS Mathematics, 2022, 7(9): 15714-15740. doi: 10.3934/math.2022861
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In this work, a five-parameter jerk system with one hyperbolic sine nonlinearity is proposed, in which ε is a small parameter, and a, b, c, d are some other parameters. For ε=0, the system is Z2 symmetric. For ε≠0, the system loses the symmetry. For the symmetrical case, the pitchfork bifurcation and Hopf bifurcation of the origin are studied analytically by Sotomayor's theorem and Hassard's formulas, respectively. These bifurcations can be either supercritical or subcritical depending on the governing parameters. In comparison, it is much more restrictive for the origin of the Lorenz system: Only a supercritical pitchfork bifurcation is available. Thus, the symmetrical system can exhibit very rich local bifurcation structures. The continuation of local bifurcations leads to the main contribution of this work, i.e., the discovery of two basic mechanisms of chaotic motions for the jerk systems. For four typical cases, Cases A–D, by varying the parameter a, the mechanisms are identified by means of bifurcation diagrams. Cases A and B are Z2 symmetric, while Cases C and D are asymmetric (caused by constant terms). The forward period-doubling routes to chaos are observed for Cases A and C; meanwhile, the backward period-doubling routes to chaos are observed for Cases B and D. The dynamical behaviors of these cases are studied via phase portraits, two-sided Poincaré sections and Lyapunov exponents. Using Power Simulation (PSIM), a circuit simulation model for a chaotic jerk system is created. The circuit simulations match the results of numerical simulations, which further validate the dynamical behavior of the jerk system.
Let q≥3 be an integer, and χ be a Dirichlet character modulo q. The characters of the rational polynomial are defined as follows:
N+M∑x=N+1χ(f(x)), |
where M and N are any given positive integers, and f(x) is a rational polynomial. For example, when f(x)=x, for any non-principal Dirichlet character χ mod q, Pólya [1] and Vinogradov [2] independently proved that
|N+M∑x=N+1χ(x)|<√qlnq, |
and we call it Pólya-Vinogradov inequality.
When q=p is an odd prime, χ is a p-th order character modulo p, Weil [3] proved
N+M∑x=N+1χ(f(x))≪p12lnp, |
where f(x) is not a perfect p-th power modulo p, A≪B denotes |A|<kB for some constant k, which in this case depends on the degree of f.
Many authors have obtained numerous results for various forms of f(x). For example, W. P. Zhang and Y. Yi [4] constructed a special polynomial as f(x)=(x−r)m(x−s)n and deduced
|q∑a=1χ((a−r)m(a−s)n)|=√q, |
where (r−s,q)=1, and χ is a primitive character modulo q. This shows the power of q in Weil's result is the best possible!
Also, when χ is a primitive character mod q, W. P. Zhang and W. L. Yao [5] obtained
q∑a=1χ(am(1−a)m)=√q¯χ(4m), |
where q is an odd perfect square and m is any positive integer with (m,q)=1.
When q=pα11pα22⋯pαss is a square full number with pi≡3mod4, χ=χ1χ2…χs with χi being any primitive even character mod pαii(i=1,2,…,s), W. P. Zhang and T. T. Wang [6] obtained the identity
|q∑a=1′χ(ma2k−1+n¯a)|=√q∏p|q(1+(mn(2k−1)p)), | (1.1) |
where a⋅¯a≡1modq, and (∗p) denotes the Legendre symbol. Besides, k, m and n also satisfying some special conditions. Other related work about Dirichlet characters of the rational polynomials can be found in references [7,8,9,10,11,12,13,14]. Inspired by these, we will study the sum
q∑a=1′χ(ma+¯a). |
Following the way in [6], we obtain W. P. Zhang and T. T. Wang's identity (1.1) under a more relaxed situation. Then by adding some new ingredients, we derive some new identities for the fourth power mean of it.
Noting that if χ is an odd character modulo q, m is a positive integer with (m,q)=1, we can get
q∑a=1′χ(ma+¯a)=q∑a=1′χ(−ma+¯(−a))=−q∑a=1′χ(ma+¯a). |
That is to say, under this condition,
q∑a=1′χ(ma+¯a)=0. |
So, we will only discuss the case of χ an even character. To the best of our knowledge, the following identities dealing with arbitrary odd square-full number cases are new and have not appeared before.
Theorem 1.1. Let q=pα11pα22⋯pαss be an odd square-full number, χi be any primitive even character mod pαii (i=1,2,…,s) and χ=χ1χ2⋯χs. Then for any integer m with (m,q)=1, we have the identity
|q∑a=1′χ(ma+¯a)|=√q∏p∣q(1+(mp)), |
where ∏p∣q denotes the product over all distinct prime divisors p of q.
Remark 1.1. It is obvious that Theorem 1.1 is W. P. Zhang and T. T. Wang's identity (1.1) with k=n=1 by removing the condition pi≡3mod4 (i=1,2,…,s). Besides, using our results, we can directly obtain the absolute values of the sums of Dirichlet characters satisfying some conditions, which avoids complex calculations. What's more, the result of Theorem 1.1 also shows that the order of q in Weil's result can not be improved.
To understand the result better, we give the following examples:
Example 1.1. Let q=32, χ be a Dirichlet character modulo 9 defined as follows:
χ(n)={e2πi⋅ind2n3,if (n,9)=1;0,if (n,9)>1. |
Obviously, χ is a primitive even character modulo 9. Taking m=1,2, then we have
|9∑a=1′χ(ma+¯a)|=|9∑a=1′χ(a+¯a)|=|3χ(2)+3χ(7)|=|3e2πi3+3e2πi⋅43|=6,|9∑a=1′χ(ma+¯a)|=|9∑a=1′χ(2a+¯a)|=|2χ(3)+2χ(6)+2χ(9)|=0. |
Example 1.2. Let q=52, χ be a primitive even character modulo 25 defined as follows:
χ(n)={e2πi⋅ind2n5,if (n,25)=1;0,if (n,25)>1. |
Taking m=1,2, then we have
|25∑a=1′χ(ma+¯a)|=|25∑a=1′χ(a+¯a)|=|5χ(2)+5χ(23)|=|5e2πi5+5e2πi⋅115|=10,|25∑a=1′χ(ma+¯a)|=|25∑a=1′χ(2a+¯a)|=|4χ(2)+4χ(3)+4χ(7)+4χ(8)+4χ(12)|=|4e2πi5+4e2πi⋅75+4e2πi⋅55+4e2πi⋅35+4e2πi⋅95|=0. |
Example 1.3. Let q=132, χ be a primitive even character modulo 169 defined as follows:
χ(n)={e2πi⋅ind2n13,if (n,169)=1;0,if (n,169)>1. |
Taking m=1,2, then we have
|169∑a=1′χ(ma+¯a)|=|169∑a=1′χ(a+¯a)|=|4χ(1)+26χ(2)+4χ(4)+4χ(9)+4χ(12)+4χ(14)+4χ(17)+4χ(22)+4χ(25)+4χ(27)+4χ(30)+4χ(35)+4χ(38)+4χ(40)+4χ(43)+4χ(48)+4χ(51)+4χ(53)+4χ(56)+4χ(61)+4χ(64)+4χ(66)+4χ(69)+4χ(74)+4χ(77)+4χ(79)+4χ(82)|=|8+8eπi13+34e2πi13+8e3πi13+8e4πi13+8e5πi13+8e6πi13+8e7πi13+8e8πi13+8e9πi13+8e10πi13+8e11πi13+8e12πi13|=26, |
|169∑a=1′χ(ma+¯a)|=|169∑a=1′χ(2a+¯a)|=|4χ(2)+4χ(3)+4χ(5)+4χ(8)+4χ(10)+4χ(11)+4χ(15)+4χ(16)+4χ(18)+4χ(21)+4χ(23)+4χ(24)+4χ(28)+4χ(29)+4χ(31)+4χ(34)+4χ(36)+4χ(37)+4χ(41)+4χ(42)+4χ(44)+4χ(47)+4χ(49)+4χ(50)+4χ(54)+4χ(55)+4χ(57)+4χ(60)+4χ(62)+4χ(63)+4χ(67)+4χ(68)+4χ(70)+4χ(73)+4χ(75)+4χ(76)+4χ(80)+4χ(81)+4χ(83)|=|12+12eπi13+12e2πi13+12e3πi13+12e4πi13+12e5πi13+12e6πi13+12e7πi13+12e8πi13+12e9πi13+12e10πi13+12e11πi13+12e12πi13|=0. |
The above examples can be easily achieved by our Theorem 1.1. From Theorem 1.1, we may immediately obtain the following two corollaries:
Corollary 1.1. Let q=pα11pα22⋯pαss be an odd square-full number, χi be any primitive even character mod pαi (i=1,2,…,s) and χ=χ1χ2⋯χs. Then for any integer m with (m,q)=1, we have the identity
|q∑a=1′χ(ma+¯a)|={2ω(q)√q, if m is a quadratic residue modulo q;0, otherwise, |
where ω(q) denotes the number of all distinct prime divisors of q.
Corollary 1.2. Let q=pα11pα22⋯pαss be an odd number with αi≥1 (i=1,2,…,s), χi be any primitive even character mod pαii and χ=χ1χ2⋯χs. Then for any integer m with (m,q)=1, we have the inequality
|q∑a=1′χ(ma+¯a)|≤2ω(q)√q. |
Theorem 1.2. Let q=pα11pα22⋯pαss be an odd square-full number, χi be any primitive even character mod pαii (i=1,2,…,s) and χ=χ1χ2⋯χs. Then for any integers k and m with k≥1 and (m,q)=1, we have the identity
∑∗χmodqχ(−1)=1|q∑a=1′χ(ma+¯a)|2k=qk2ω(q)J(q)∏p∣q(1+(mp))2k, |
where J(q) denotes the number of primitive characters modulo q, and ∑χmodq∗ denotes the summation over all primitive characters modulo q.
Example 1.4. Taking q=52, m=1,2, then we have
∑∗χmod25χ(−1)=1|25∑a=1′χ(ma+¯a)|2k=∑∗χmod25χ(−1)=1|25∑a=1′χ(a+¯a)|2k=8⋅102k,∑∗χmod25χ(−1)=1|25∑a=1′χ(ma+¯a)|2k=∑∗χmod25χ(−1)=1|25∑a=1′χ(2a+¯a)|2k=0, |
which can be easily achieved by our Theorem 1.2.
Taking k=2 in Theorem 1.2, we may immediately obtain the followings:
Corollary 1.3. Let q=pα11pα22⋯pαss be an odd square-full number, χi be any primitive even character mod pαii (i=1,2,…,s) and χ=χ1χ2⋯χs. Then for any integer m with (m,q)=1, we have the identity
∑∗χmodqχ(−1)=1|q∑a=1′χ(ma+¯a)|4=q22ω(q)J(q)∏p∣q(1+(mp))4. |
Corollary 1.4. Let q=pα11pα22⋯pαss be an odd square-full number, χi be any primitive even character mod pαii (i=1,2,…,s) and χ=χ1χ2⋯χs. Then we have the identity
∑∗χmodqχ(−1)=1|q∑a=1′χ(ma+¯a)|4={8ω(q)q2J(q), if m is a quadratic residue modulo q;0, otherwise. |
Theorem 1.3. Let p be an odd prime, χ be any non-principal character mod p. Then for any integer m with (m,p)=1, we have the identity
∑χmodpχ(−1)=1|p−1∑a=1χ(ma+¯a)|4={2p3−6p2+4−4(p2−3p+2)(mp)+(p−1)E,if p≡3mod4;2p3−6p2+4−4(p2+p−2)(mp)+(p−1)E,if p≡1mod4, |
where
E=p−1∑a=1p−1∑b=1((a2b−1)(b−1)bp)p−1∑d=1((¯a2d−1)(d−1)dp). |
Remark 1.2. From [8], we know that when f(x) is a polynomial of odd degree n≥3, Weil's estimate ([15,16])
|p−1∑x=0(f(x)p)|≤(n−1)√p, |
implies that E<4p2−8p. Noting that q∑a=1′χ(ma+¯a) can be regarded as a dual form of Kloosterman sums, which defined as q∑a=1′e2πima+ˉaq, we can obtain some distributive properties of q∑a=1′χ(ma+¯a) from Theorem 1.2 and 1.3.
From Theorem 1.3, we also have the following corollaries:
Corollary 1.5. Let p be an odd prime, χ be any non-principal character mod p. Then for any quadratic residue m mod p, we have the identity
∑χmodpχ(−1)=1|p−1∑a=1χ(ma+¯a)|4={2p3−10p2+12p−4+(p−1)E,if p≡3mod4;2p3−10p2−4p+12+(p−1)E,if p≡1mod4. |
Corollary 1.6. Let p be an odd prime, χ be any non-principal character mod p. Then for any quadratic non-residue m mod p, we have the identity
∑χmodpχ(−1)=1|p−1∑a=1χ(ma+¯a)|4={2p3−2p2−12p+4+(p−1)E,if p≡3mod4;2p3−2p2+4p−4+(p−1)E,if p≡1mod4. |
To prove our Theorems, we need some Lemmas as the following:
Lemma 2.1. Let q, q1, q2 be integers with q=q1q2 and (q1,q2)=1, χi be any non-principal character mod qi (i=1,2). Then for any integer m with (m,q)=1 and χ=χ1χ2, we have the identity
q∑a=1′χ(ma+¯a)=q1∑b=1′χ1(mb+¯b)q2∑c=1′χ2(mc+¯c). |
Proof. From the properties of Dirichlet characters, we have
q∑a=1′χ(ma+¯a)=q1q2∑a=1′χ1χ2(ma+¯a)=q1∑b=1′q2∑c=1′χ1χ2(m(bq2+cq1)+¯bq2+cq1)=q1∑b=1′q2∑c=1′χ1(m(bq2+cq1)+¯bq2+cq1)χ2(m(bq2+cq1)+¯bq2+cq1)=q1∑b=1′χ1(mbq2+¯bq2)q2∑c=1′χ2(mcq1+¯cq1)=q1∑b=1′χ1(mb+¯b)q2∑c=1′χ2(mc+¯c). |
This completes the proof of Lemma 2.1.
Lemma 2.2. Let p be an odd prime, α and m be integers with α≥1 and (m,p)=1. Then for any primitive even character χ mod pα, we have the identity
pα∑a=1′χ(ma+¯a)=χ1(m)τ2(¯χ1)τ(¯χ)(1+χ02(m)τ2(χ02¯χ1)τ2(¯χ1)), |
where χ02=(∗p), τ(χ)=pα∑a=1χ(a)e(apα), χ1 is a primitive character mod pα and χ=χ21.
Proof. For any primitive even character χ mod pα, there exists one primitive character χ1 mod pα such that χ=χ21. From the properties of Gauss sum, we can obtain
pα∑a=1′χ(ma+¯a)=1τ(¯χ)pα∑a=1′pα∑b=1¯χ(b)e(b(ma+¯a)pα)=1τ(¯χ)pα∑a=1¯χ(a)pα∑b=1¯χ(b)e(b(ma2+1)pα)=1τ(¯χ)pα∑b=1¯χ(b)e(bpα)pα∑a=1¯χ(a)e(bma2pα)=1τ(¯χ)pα∑b=1¯χ(b)e(bpα)pα∑a=1¯χ1(a2)e(bma2pα)=1τ(¯χ)pα∑b=1¯χ(b)e(bpα)pα∑a=1(1+χ02(a))¯χ1(a)e(bmapα)=1τ(¯χ)pα∑b=1¯χ(b)e(bpα)pα∑a=1¯χ1(a)e(bmapα)+1τ(¯χ)pα∑b=1¯χ(b)e(bpα)pα∑a=1χ02(a)¯χ1(a)e(bmapα):=B1+B2. |
Now we compute B1 and B2 respectively.
B1=1τ(¯χ)pα∑b=1¯χ(b)e(bpα)pα∑a=1¯χ1(a)e(bmapα)=1τ(¯χ)pα∑b=1¯χ(b)χ1(bm)e(bpα)pα∑a=1¯χ1(bma)e(bmapα)=χ1(m)τ(¯χ1)τ(¯χ)pα∑b=1¯χ(b)χ1(b)e(bpα)=χ1(m)τ(¯χ1)τ(¯χ)pα∑b=1¯χ1(b)e(bpα)=χ1(m)τ2(¯χ1)τ(¯χ). |
Similarly, we have
B2=χ1(m)χ02(m)τ2(χ02¯χ1)τ(¯χ). |
Therefore, we can obtain
pα∑a=1′χ(ma+¯a)=χ1(m)τ2(¯χ1)τ(¯χ)(1+χ02(m)τ2(χ02¯χ1)τ2(¯χ1)). |
Lemma 2.3. Let p be an odd prime. Then for any integer n, we have the identity
p∑a=1(a2+np)={−1,if (n,p)=1;p−1,if (n,p)=p. |
Proof. See Theorem 8.2 of [17].
Lemma 2.4. Let p be an odd prime. Then we have the identity
p−2∑a=2p−1∑b=1((a2b−1)(b−1)bp)=2×(−1)p−12+2. |
Proof. From the properties of character sum, we have
p−2∑a=2p−1∑b=1((a2b−1)(b−1)bp)=p−1∑b=1(b−1p)p−2∑a=2((a2b−1)bp)=p−1∑b=1(b−1p)p−2∑a=2(b2(a2−¯b)p)=p−1∑b=1(b−1p)p−2∑a=2(a2−¯bp)=p−1∑b=1(b−1p)(p∑a=1(a2−¯bp)−(1−¯bp)−((p−1)2−¯bp)−(p2−¯bp))=p−1∑b=1(b−1p)(−1−2(1−¯bp)−(−¯bp))=−p−1∑b=1(b−1p)−2p−1∑b=1(b−1p)(1−¯bp)−p−1∑b=1(b−1p)(−¯bp)=−p−2∑b=0(bp)−2p−1∑b=1(b−1p)((1−¯b)b2p)−p−1∑b=1(¯b−1p)=−2p−2∑b=0(bp)−2p−1∑b=1((b−1)2bp)=−2(p−1∑b=0(bp)−(p−1p))−2×(−1)=2×(−1)p−12+2. |
This completes the proof of Lemma 2.4.
Now we come to prove our Theorems.
Firstly, we prove Theorem 1.1. With the help of Lemma 2 in [6], when α≥2, we have
τ2(χ02¯χ1)τ2(¯χ1)=(1p)2=1, |
which implies from Lemma 2.2, we can obtain
|pα∑a=1′χ(ma+¯a)|=|χ1(m)τ2(¯χ1)τ(¯χ)(1+(mp))|=√pα(1+(mp)). |
Then, applying Lemma 2.1, we can obtain
|q∑a=1′χ(ma+¯a)|=|pα11∑a1=1′χ1(ma1+¯a1)|⋯|pαss∑as=1′χs(mas+¯as)|=√q∏p∣q(1+(mp)). |
This completes the proof of Theorem 1.1.
Then, from Lemma 2.1 and Lemma 2.2, we can prove Theorem 1.2 as following:
∑∗χmodqχ(−1)=1|q∑a=1′χ(ma+¯a)|2k=∑∗χ1modpα11χ1(−1)=1|pα11∑a1=1′χ1(ma1+¯a1)|2k⋯∑∗χsmodpαssχs(−1)=1|pαss∑as=1′χs(mas+¯as)|2k=s∏i=1[12J(pαii)pkαii|1+(mpi)|2k]=qk2ω(q)J(q)∏p∣q(1+(mp))2k. |
Finally, we prove Theorem 1.3. For any integer m with (m,p)=1, we have
p−1∑a=1χ(ma+¯a)=p−1∑u=1χ(u)p−1∑a=1am+¯a≡umodp1=p−1∑u=1χ(u)p−1∑a=1a2m2−amu+m≡0modp1=p−1∑u=1χ(u)p−1∑a=0(2am−u)2≡u2−4mmodp1=p−1∑u=1χ(u)p−1∑a=0a2≡u2−4mmodp1=p−1∑u=1χ(u)(1+(u2−4mp))=p−1∑u=1χ(u)(u2−4mp)=χ(2)p−1∑u=1χ(u)(u2−mp). |
So from the orthogonality of Dirichlet characters and the properties of reduced residue system modulo p, we have
∑χmodpχ(−1)=1|p−1∑a=1χ(ma+¯a)|4=∑χmodpχ(−1)=1|χ(2)p−1∑u=1χ(u)(u2−mp)|2|χ(2)p−1∑u=1χ(u)(u2−mp)|2=∑χmodpχ(−1)=1p−1∑a=1p−1∑b=1p−1∑c=1p−1∑d=1χ(ac¯bd)(a2−mp)(b2−mp)(c2−mp)(d2−mp)=∑χmodpχ(−1)=1p−1∑a=1p−1∑b=1p−1∑c=1p−1∑d=1χ(ac)(a2b2−mp)(b2−mp)(c2d2−mp)(d2−mp)=p−1∑a=1p−1∑b=1p−1∑c=1p−1∑d=1(a2b2−mp)(b2−mp)(c2d2−mp)(d2−mp)∑χmodpχ(−1)=1χ(ac)=p−12p−1∑a=1p−1∑b=1p−1∑c=1p−1∑d=1a≡¯cmodp(a2b2−mp)(b2−mp)(c2d2−mp)(d2−mp)+p−12p−1∑a=1p−1∑b=1p−1∑c=1p−1∑d=1a≡−¯cmodp(a2b2−mp)(b2−mp)(c2d2−mp)(d2−mp)=(p−1)p−1∑a=1p−1∑b=1p−1∑d=1(a2b2−mp)(b2−mp)(¯a2d2−mp)(d2−mp)=(p−1)p−1∑a=1p−1∑b=1(1+(bp))(a2b−mp)(b−mp)p−1∑d=1(1+(dp))(¯a2d−mp)(d−mp)=(p−1)p−1∑a=1p−1∑b=1(a2b−1p)(b−1p)p−1∑d=1(¯a2d−1p)(d−1p)+(p−1)p−1∑a=1p−1∑b=1(a2b−1p)(b−1p)p−1∑d=1(mp)((¯a2d−1)(d−1)dp)+(p−1)p−1∑a=1p−1∑b=1(mp)((a2b−1)(b−1)bp)p−1∑d=1(¯a2d−1p)(d−1p)+(p−1)p−1∑a=1p−1∑b=1(mp)((a2b−1)(b−1)bp)p−1∑d=1(mp)((¯a2d−1)(d−1)dp):=A1+A2+A3+A4. |
Now we compute A1, A2, A3, A4 respectively. Noticing that χ(−1)=1, from the properties of the complete residue system modulo p, we have
p−1∑b=1(a2b−1p)(b−1p)=p−1∑b=0(a2b−1p)(b−1p)−1=p−1∑b=0(4a2p)((a2b−1)(b−1)p)−1=p−1∑b=0((2a2b−a2−1)2−(a2−1)2p)−1=p−1∑b=0(b2−(a2−1)2p)−1. |
Applying Lemma 2.3, we can get
A1=(p−1)p−1∑a=1p−1∑b=1(a2b−1p)(b−1p)p−1∑d=1(¯a2d−1p)(d−1p)=(p−1)p−1∑a=1(p−1∑b=0(b2−(a2−1)2p)−1)(p−1∑d=0(d2−(¯a2−1)2p)−1)=(p−1)[2p−1∑b=0(b2p)p−1∑d=0(d2p)+p−2∑a=2p−1∑b=0(b2−(a2−1)2p)p−1∑d=0(d2−(¯a2−1)2p)]−2(p−1)p−1∑a=1p−1∑b=0(b2−(a2−1)2p)+(p−1)2=2p3−6p2+4. |
Then, we compute A2. With the aid of Lemma 2.4, we have
A2=(p−1)p−1∑a=1p−1∑b=1(a2b−1p)(b−1p)p−1∑d=1(mp)((¯a2d−1)(d−1)dp)=(p−1)p−1∑a=1[p−1∑b=0(b2−(a2−1)2p)−1]p−1∑d=1(mp)((¯a2d−1)(d−1)dp)=(p−1)2p−1∑d=1(mp)((d−1)2dp)−(p−1)p−2∑a=2p−1∑d=1(mp)((¯a2d−1)(d−1)dp)+(p−1)2p−1∑d=1(mp)(((p−1)2d−1)(d−1)dp)−(p−1)p−1∑a=1p−1∑d=1(mp)((¯a2d−1)(d−1)dp)=(p2−3p+2)[p−1∑d=1(mp)((d−1)2dp)+p−1∑d=1(mp)(((p−1)2d−1)(d−1)dp)]−2(p−1)p−2∑a=2p−1∑d=1(mp)((a2d−1)(d−1)dp)=2(p2−3p+2)(mp)p−1∑d=1((d−1)2dp)−4(p−1)[(−1)p−12+1](mp)=2(p2−3p+2)(mp)p−1∑b=2(bp)−4(p−1)[(−1)p−12+1](mp)=−2(p2−3p+2)(mp)−4(p−1)[(−1)p−12+1](mp). |
Similarly, we have
A3=−2(p2−3p+2)(mp)−4(p−1)[(−1)p−12+1](mp). |
Note that
A4=(p−1)p−1∑a=1p−1∑b=1((a2b−1)(b−1)bp)p−1∑d=1((¯a2d−1)(d−1)dp), |
which completes the proof of Theorem 1.3.
Three Theorems are stated in the main results. The Theorem 1.1 obtains an exact computational formula for q∑a=1′χ(ma+¯a), which broadens the scope of q by removing the condition p≡3mod4 in the previous article, where p is the prime divisor of q. The Theorem 1.2 derives a new identity for the mean value of it by adding some different ingredients. What's more, the Theorem 1.3 bridges the fourth power of Dirichlet characters with Legendre symbols of certain polynomials, which may be useful in the related future research. However, due to some technical reasons, we can only deal with the odd square-full number q case.
The authors would like to thank the referees for their very helpful and detailed comments, which have significantly improved the presentation of this paper. This work is supported by the National Natural Science Foundation of China (No. 11871317), and the Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China (No. 2021JC-29).
The authors declare that there are no conflicts of interest regarding the publication of this paper.
[1] |
A. Jones, N. Strigul, Is spread of COVID-19 a chaotic epidemic? Chaos Solitons Fract., 142 (2021), 110376. https://doi.org/10.1016/j.chaos.2020.110376 doi: 10.1016/j.chaos.2020.110376
![]() |
[2] | H. Iro, A modern approach to cassical mechanics, Singarpore: World Scientific, 2015. https://doi.org/10.1142/9655 |
[3] | A. T. Johnson, Biology for engineers, Boca Raton, Florida: CRC Press, 2018. https://doi.org/10.1201/9781351165648 |
[4] | K. H. Sun, Chaotic secure communication: Principles and technologies, Beijing: Tsinghua University Press, 2016. |
[5] | E. N. Lorenz, Deterministic nonperiodic flow, J. Atmos. Sci., 20 (1963), 130–141. |
[6] |
O. E. Rössler, An equation for continuous chaos, Phys. Lett. A, 57 (1976), 397–398. https://doi.org/10.1016/0375-9601(76)90101-8 doi: 10.1016/0375-9601(76)90101-8
![]() |
[7] |
G. R. Chen, T. Ueta, Yet another chaotic attractor, Int. J. Bifurcat. Chaos, 9 (1999), 1465–1466. https://doi.org/10.1142/S0218127499001024 doi: 10.1142/S0218127499001024
![]() |
[8] |
Q. G. Yang, Z. C. Wei, G. R. Chen, An unusual 3D autonomous quadratic chaotic system with two stable node-foci, Int. J. Bifurcat. Chaos, 20 (2010), 1061–1083. https://doi.org/10.1142/S0218127410026320 doi: 10.1142/S0218127410026320
![]() |
[9] | J. C. Sprott, Elegant chaos: Algebraically simple chaotic flows, Singapore: World Scientific, 2010. |
[10] |
J. C. Sprott, Strange attractors with various equilibrium types, Eur. Phys. J. Spec. Top., 224 (2015), 1409–1419. https://doi.org/10.1140/epjst/e2015-02469-8 doi: 10.1140/epjst/e2015-02469-8
![]() |
[11] |
Z. Wang, Z. C. Wei, K. H. Sun, S. B. He, H. H. Wang, Q. Xu, et al., Chaotic flows with special equilibria, Eur. Phys. J. Spec. Top., 229 (2020), 905–919. https://doi.org/10.1140/epjst/e2020-900239-2 doi: 10.1140/epjst/e2020-900239-2
![]() |
[12] |
G. A. Leonov, N. V. Kuznetsov, Hidden attractors in dynamical systems. From hidden oscillations in Hilbert-Kolmogorov, Aizerman, and Kalman problems to hidden chaotic attractor in Chua circuits, Int. J. Bifurcat. Chaos, 23 (2013), 1330002. https://doi.org/10.1142/S0218127413300024 doi: 10.1142/S0218127413300024
![]() |
[13] |
S. N. Chowdhurry, D. Ghosh, Hidden attractors: A new chaotic system without equilibria, Eur. Phys. J. Spec. Top., 229 (2020), 1299–1308. https://doi.org/10.1140/epjst/e2020-900166-7 doi: 10.1140/epjst/e2020-900166-7
![]() |
[14] |
X. Wang, A. Akgul, S. Cicek, V. T. Pham, D. V. Hoang, A chaotic system with two stable equilibrium points: Dynamics, circuit realization and communication application, Int. J. Bifurcat. Chaos, 27 (2017), 1750130. https://doi.org/10.1142/S0218127417501309 doi: 10.1142/S0218127417501309
![]() |
[15] |
S. Jafari, J. C. Sprott, V. T. Pham, C. Volos, C. B. Li, Simple chaotic 3D flows with surfaces of equilibria, Nonlinear Dyn., 86 (2016), 1349–1358. https://doi.org/10.1007/s11071-016-2968-x doi: 10.1007/s11071-016-2968-x
![]() |
[16] |
S. T. Kingni, V. T. Pham, S. Jafari, P. Woafo, A chaotic system with an infinite number of equilibrium points located on a line and on a hyperbola and its fractional-order form, Chaos Solitons Fract., 99 (2017), 209–218. https://doi.org/10.1016/j.chaos.2017.04.011 doi: 10.1016/j.chaos.2017.04.011
![]() |
[17] |
Y. J. Dong, G. Y. Wang, H. H. Iu, G. R. Chen, L. Chen, Coexisting hidden and self-excited attractors in a locally active memristor-based circuit, Chaos, 30 (2020), 103123. https://doi.org/10.1063/5.0002061 doi: 10.1063/5.0002061
![]() |
[18] |
T. Kapitaniak, G. A. Leonov, Multistability: Uncovering hidden attractors, Eur. Phys. J. Spec. Top., 224 (2015), 1405–1408. https://doi.org/10.1140/epjst/e2015-02468-9 doi: 10.1140/epjst/e2015-02468-9
![]() |
[19] |
N. Wang, G. S. Zhang, N. V. Kuznetsov, H. Bao, Hidden attractors and multistability in a modified Chua's circuit, Commun. Nonlinear Sci. Numer. Simul., 92 (2021), 105494. https://doi.org/10.1016/j.cnsns.2020.105494 doi: 10.1016/j.cnsns.2020.105494
![]() |
[20] | X. Wang, N. V. Kuznetsov, G. R. Chen, Chaotic systems with multistability and hidden attractors, New York: Springer, 2021. https://doi.org/10.1007/978-3-030-75821-9 |
[21] |
M. N. Zavareh, F. Nazarimehr, K. Rajagopal, S. Jafari, Hidden attractor in a passive motion model of compass-gait robot, Int. J. Bifurcat. Chaos, 28 (2018), 1850171. https://doi.org/10.1142/S0218127418501717 doi: 10.1142/S0218127418501717
![]() |
[22] |
A. Prasad, Existence of perpetual points in nonlinear dynamical systems and its applications, Int. J. Bifurcat. Chaos, 25 (2015), 1530005. https://doi.org/10.1142/S0218127415300050 doi: 10.1142/S0218127415300050
![]() |
[23] |
D. Dudkowski, A. Prasad, T. Kapitaniak, Perpetual points and hidden attractors in dynamical systems, Phys. Lett. A, 379 (2015), 2591–2596. https://doi.org/10.1016/j.physleta.2015.06.002 doi: 10.1016/j.physleta.2015.06.002
![]() |
[24] |
F. Nazarimehr, B. Saedi, S. Jafari, J. C. Sprott, Are perpetual points sufficient for locating hidden attractors? Int. J. Bifurcat. Chaos, 27(2017), 1750037. https://doi.org/10.1142/S0218127417500377 doi: 10.1142/S0218127417500377
![]() |
[25] |
D. Dudkowski, A. Prasad, T. Kapitaniak, Describing chaotic attractors: Regular and perpetual points, Chaos, 28 (2018), 033604. https://doi.org/10.1063/1.4991801 doi: 10.1063/1.4991801
![]() |
[26] |
A. K. Farhan, N. M. G. Al-Saidi, A. T. Maolood, F. Nazarimehr, I. Hussain, Entropy analysis and image encryption application based on a new chaotic system crossing a cylinder, Entropy, 21 (2019), 1–14. https://doi.org/10.3390/e21100958 doi: 10.3390/e21100958
![]() |
[27] |
U. Çavuçoğlu, S. Panahi, A. Akgül, S. Jafari, S. Kaçar, A new chaotic system with hidden attractor and its engineering applications: Analog circuit realization and image encryption, Analog Integr. Circ. Sig. Process, 98 (2019), 85–99. https://doi.org/10.1007/s10470-018-1252-z doi: 10.1007/s10470-018-1252-z
![]() |
[28] |
A. N. Pisarchik, U. Feudel, Control of multistability, Phys. Rep., 540 (2014), 167–218. https://doi.org/10.1016/j.physrep.2014.02.007 doi: 10.1016/j.physrep.2014.02.007
![]() |
[29] |
S. Morfu, B. Nofiele, P. Marquié, On the use of multistability for image processing, Phys. Lett. A, 367 (2007), 192–198. https://doi.org/10.1016/j.physleta.2007.02.086 doi: 10.1016/j.physleta.2007.02.086
![]() |
[30] |
Z. T. Njitacke, S. D. Isaac, T. Nestor, J. Kengne, Window of multistability and its control in a simple 3D Hopfield neural network: Application to biomedical image encryption, Neural Comput. Appl., 33 (2021), 6733–6752. https://doi.org/10.1007/s00521-020-05451-z doi: 10.1007/s00521-020-05451-z
![]() |
[31] | M. Lines, Nonlinear dynamical systems in economics, CISM, Vol. 476, Vienna: Springer, 2005. https://doi.org/10.1007/3-211-38043-4 |
[32] |
B. Chen, X. X. Cheng, H. Bao, M. Chen, Q. Xu, Extreme multistability and its incremental integral reconstruction in a non-autonomous memcapacitive oscillator, Mathematics, 10 (2022), 1–13. https://doi.org/10.3390/math10050754 doi: 10.3390/math10050754
![]() |
[33] |
J. C. Sprott, S. Jafari, A. J. M. Khalaf, T. Kapitaniak, Megastability: Coexistence of a countable infinity of nested attractors in a periodically-forced oscillator with spatially-periodic damping, Eur. Phys. J. Spec. Top., 226 (2017), 1979–1985. https://doi.org/10.1140/epjst/e2017-70037-1 doi: 10.1140/epjst/e2017-70037-1
![]() |
[34] |
V. Patidar, K. K. Sud, Bifurcation and chaos in simple jerk dynamical systems, Pramana, 64 (2005), 75–93. https://doi.org/10.1007/BF02704532 doi: 10.1007/BF02704532
![]() |
[35] |
G. Innocenti, A. Tesi, R. Genesio, Complex behavior analysis in quadratic jerk systems via frequency domain Hopf bifurcation, Int. J. Bifurcat. Chaos, 20 (2010), 657–667. https://doi.org/10.1142/S0218127410025946 doi: 10.1142/S0218127410025946
![]() |
[36] |
B. Sang, B. Huang, Zero-Hopf bifurcations of 3D quadratic jerk system, Mathematics, 8 (2020), 1–19. https://doi.org/10.3390/math8091454 doi: 10.3390/math8091454
![]() |
[37] |
Z. C. Wei, J. C. Sprott, H. Chen, Elementary quadratic chaotic flows with a single non-hyperbolic equilibrium, Phys. Lett. A, 379 (2015), 2184–2187. https://doi.org/10.1016/j.physleta.2015.06.040 doi: 10.1016/j.physleta.2015.06.040
![]() |
[38] |
K. E. Chlouverakis, J. C. Sprott, Chaotic hyperjerk systems, Chaos Solitons Fract., 28 (2006), 739–746. https://doi.org/10.1016/j.chaos.2005.08.019 doi: 10.1016/j.chaos.2005.08.019
![]() |
[39] |
F. Y. Dalkiran, J. C. Sprott, Simple chaotic hyperjerk system, Int. J. Bifurcat. Chaos, 26 (2016), 1650189. https://doi.org/10.1142/S0218127416501893 doi: 10.1142/S0218127416501893
![]() |
[40] |
J. P. Singh, V. T. Pham, T. Hayat, S. Jafari, F. E. Alsaadi, B. K. Roy, A new four-dimensional hyperjerk system with stable equilibrium point, circuit implementation, and its synchronization by using an adaptive integrator backstepping control, Chinese Phys. B, 27 (2018), 100501. https://doi.org/10.1088/1674-1056/27/10/100501 doi: 10.1088/1674-1056/27/10/100501
![]() |
[41] |
G. D. Leutcho, J. Kengne, L. K. Kengne, Dynamical analysis of a novel autonomous 4-D hyperjerk circuit with hyperbolic sine nonlinearity: Chaos, antimonotonicity and a plethora of coexisting attractors, Chaos Solitons Fract., 107 (2018), 67–87. https://doi.org/10.1016/j.chaos.2017.12.008 doi: 10.1016/j.chaos.2017.12.008
![]() |
[42] |
I. Ahmad, B. Srisuchinwong, W. San-Um, On the first hyperchaotic hyperjerk system with no equilibria: A simple circuit for hidden attractors, IEEE Access, 6 (2018), 35449–35456. https://doi.org/10.1109/ACCESS.2018.2850371 doi: 10.1109/ACCESS.2018.2850371
![]() |
[43] |
P. Ketthong, B. Srisuchinwong, A damping-tunable snap system: From dissipative hyperchaos to conservative chaos, Entropy, 24 (2022), 1–14. https://doi.org/10.3390/e24010121 doi: 10.3390/e24010121
![]() |
[44] |
M. Joshi, A. Ranjan, An autonomous simple chaotic jerk system with stable and unstable equilibria using reverse sine hyperbolic functions, Int. J. Bifurcat. Chaos, 30 (2020), 2050070. https://doi.org/10.1142/S0218127420500704 doi: 10.1142/S0218127420500704
![]() |
[45] |
K. Rajagopal, S. T. Kingni, G. F. Kuiate, V. K. Tamba, V. T. Pham, Autonomous jerk oscillator with cosine hyperbolic nonlinearity: Analysis, FPGA implementation, and synchronization, Adv. Math. Phys., 2018 (2018), 1–12. https://doi.org/10.1155/2018/7273531 doi: 10.1155/2018/7273531
![]() |
[46] |
C. Volos, A. Akgul, V. T. Pham, I. Stouboulos, I. Kyprianidis, A simple chaotic circuit with a hyperbolic sine function and its use in a sound encryption scheme, Nonlinear Dyn., 89 (2017), 1047–1061. https://doi.org/10.1007/s11071-017-3499-9 doi: 10.1007/s11071-017-3499-9
![]() |
[47] |
J. Kengne, Z. T. Njitacke, A. N. Negou, M. F. Tsostop, H. B. Fotsin, Coexistence of multiple attractors and crisis route to chaos in a novel chaotic jerk circuit, Int. J. Bifurcat. Chaos, 26 (2016), 1650081. https://doi.org/10.1142/S0218127416500814 doi: 10.1142/S0218127416500814
![]() |
[48] |
L. K. Kengne, J. Kengne, J. R. M. Pone, H. T. K. Tagne, Symmetry breaking, coexisting bubbles, multistability, and its control for a simple jerk system with hyperbolic tangent nonlinearity, Complexity, 2020 (2020), 1–24. https://doi.org/10.1155/2020/2340934 doi: 10.1155/2020/2340934
![]() |
[49] |
Y. Li, Y. C. Zeng, J. F. Zeng, A unique jerk system with abundant dynamics: Symmetric or asymmetric bistability, tristability, and coexisting bubbles, Braz. J. Phys., 50 (2020), 153–163. https://doi.org/10.1007/s13538-019-00731-z doi: 10.1007/s13538-019-00731-z
![]() |
[50] |
M. Molaie, S. Jafari, J. C. Sprott, S. M. R. H. Golpayegani, Simple chaotic flows with one stable equilibrium, Int. J. Bifurcat. Chaos, 23 (2013), 1350188. https://doi.org/10.1142/S0218127413501885 doi: 10.1142/S0218127413501885
![]() |
[51] |
M. Liu, B. Sang, N. Wang, I. Ahmad, Chaotic dynamics by some quadratic jerk systems, Axioms, 10 (2021), 1–18. https://doi.org/10.3390/axioms10030227 doi: 10.3390/axioms10030227
![]() |
[52] |
C. B. Li, J. C. Sprott, W. J. C. Thio, Z. Y. Gu, A simple memristive jerk system, IET Circ. Device. Syst., 15 (2021), 388–392. https://doi.org/10.1049/CDS2.12035 doi: 10.1049/CDS2.12035
![]() |
[53] |
H. G. Tian, Z. Wang, P. J. Zhang, M. S. Chen, Y. Wang, Dynamic analysis and robust control of a chaotic system with hidden attractor, Complexity, 2021 (2021), 1–11. https://doi.org/10.1155/2021/8865522 doi: 10.1155/2021/8865522
![]() |
[54] |
S. Jafari, J. C. Sprott, S. M. R. H. Golpayegani, Elementary quadratic chaotic flows with no equilibria, Phys. Lett. A, 377 (2013), 699–702. https://doi.org/10.1016/j.physleta.2013.01.009 doi: 10.1016/j.physleta.2013.01.009
![]() |
[55] |
S. Zhang, Y. C. Zeng, A simple jerk-like system without equilibrium: Asymmetric coexisting hidden attractors, bursting oscillation and double full feigenbaum remerging trees, Chaos Solitons Fract., 120 (2019), 25–40. https://doi.org/10.1016/j.chaos.2018.12.036 doi: 10.1016/j.chaos.2018.12.036
![]() |
[56] |
K. Rajagopal, S. T. Kingni, G. H. Kom, V. T. Pham, A. Karthikeyan, S. Jafari, Self-excited and hidden attractors in a simple chaotic jerk system and in its time-delayed form: Analysis, electronic implementation, and synchronization, J. Korean Phys. Soc., 77 (2020), 145–152. https://doi.org/10.3938/jkps.77.145 doi: 10.3938/jkps.77.145
![]() |
[57] | J. Guckenheimer, P. Holmes, Nonlinear oscillation, dynamical systems, and bifurcations of vector fields, New York: Springer, 1983. https://doi.org/10.1007/978-1-4612-1140-2 |
[58] | L. Perko, Differential equations and dynamical systems, New York: Springer, 2001. https://doi.org/10.1007/978-1-4613-0003-8 |
[59] | B. D. Hassard, N. D. Kazarinoff, Y. H. Wan, Theory and applications of Hopf bifurcation, Cambridge: Cambridge University Press, 1981. |
[60] | Y. A. Kuznetsov, Elements of applied bifurcation theory, New York: Springer, 1998. |
[61] |
B. Sang, B. Huang, Bautin bifurcations of a financial system, Electron. J. Qual. Theory Differ. Equ., 2017 (2017), 1–22. https://doi.org/10.14232/ejqtde.2017.1.95 doi: 10.14232/ejqtde.2017.1.95
![]() |
[62] |
B. Sang, Focus quantities with applications to some finite-dimensional systems, Math. Methods Appl. Sci., 44 (2021), 464–475. https://doi.org/10.1002/mma.6750 doi: 10.1002/mma.6750
![]() |
[63] |
T. Asada, W. Semmler, Growth and finance: An intertemporal model, J. Macroeconom., 17 (1995), 623–649. https://doi.org/10.1016/0164-0704(95)80086-7 doi: 10.1016/0164-0704(95)80086-7
![]() |
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