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12 Oct 2023: Mich. 2023 ANALYSIS AND TOPOLOGY—EXAMPLES 1 PAR. 1. Let (zn) be a sequence in R2 such that zn a and zn b. ... On the other hand, show that if fn does not converge uniformly to f thenwe can find a convergent sequence xm x in [a, b] such that fn(xn) 6

19 Feb 2024: 8. Find two totally ordered sets such that neither is isomorphic to a subset of the other.Can you find three such sets? ... Is there a countable ordinal α such thatα is the αth fixed point?

11 Jan 2024: 6. Let R be an integral domain. The greatest common divisor (gcd) of non-zero elements a andb in R is an element d in R such that d divides both ... b) Show that may be identified with the set Fq{} in such a way that GL2(Fq) acts on as the group of

29 Jan 2024: 8. Let t1, t2,. be propositions such that, for every valuation v, there exists n N withv(tn) = 1. ... Show that there is a proposition b, inwhich the only primitive propositions appearing are those that appear in both a and c,such that a b and b c.

11 Oct 2023: Let A and B be subspaces of a vector space V such that V = A B, and let ‖.‖1and. ... Construct two normed spaces X and Y such that d(X, Y ) = 1 but X and Y are not.

8 Feb 2024: i) f(z)/z 0 as |z|.(ii) There exists b C and > 0 such that for every z C, |f(z) b| >. (iii) f = u iv and |u(z)| > ... Show that for any b C, there exists a sequence of points zn D(a,R) with zn 6= a such thatzn a and f(zn) b as n.

16 Nov 2023: 13. Let S be a collection of subsets of N such that for every A,B S we have A B or B A.Can S be uncountable? ... Is there an uncountable collection T of subsets of N such that A B isfinite for all distinct A,B T?

8 Feb 2024: Regarding T as a map from C into C, show that there existunique complex numbers A,B such that for every z C, T(z) = Az Bz. ... Can such a map be the restriction tothe strip of a Möbius map?

12 Oct 2023: Mich. 2023 ANALYSIS AND TOPOLOGY—EXAMPLES 1 PAR. 1. Let (zn) be a sequence in R2 such that zn a and zn b. ... On the other hand, show that if fn does not converge uniformly to f thenwe can find a convergent sequence xm x in [a, b] such that fn(xn) 6

20 Sep 2023: Provethat A contains an infinite set B such that no point of B is a convex combination of otherpoints of B. ... Show also that there is a partitionof the vertex-set as X Y such that each of e(X) and e(Y ) is at most 13e(G).

15 Jan 2024: 6. Let R be an integral domain. The greatest common divisor (gcd) of non-zero elements a andb in R is an element d in R such that d divides both ... b) Show that may be identified with the set Fq{} in such a way that GL2(Fq) acts on as the group of

10 Oct 2023: Suppose that α has minimal polynomial f over Q, and let β = α4.Find a, b, c Q such that β = a bα cα2. ... 9. Let K and L be subfields of a field M such that M/K is finite.

24 Jan 2024: 3. Let f,g : R R be such that f(x) as x a and g(y) k as y. ... Construct a function f : R R that takes every value on every interval – in otherwords for every a < b and every c there is an x with a < x < b such

21 Nov 2023: Let a,b K such that the polynomials f = Xm a, g = Xm b are irreducible. ... Use asuitable Lagrange resolvent to find a Q(ζ3) such that K = Q(ζ3, 3.

7 Mar 2024: b) Find a condition on 𝑠 such that 𝛿𝑥 𝐻𝑠(R𝑛). c) Show that 𝐻𝑡 (R𝑛) is continuously embedded in 𝐻𝑠(R𝑛) for 𝑠 < 𝑡. ... Δ2𝑢 𝑢 = 𝑓. b) Show further that there exists 𝐶 > 0 such that ‖𝑢‖𝐻 𝑠4

14 Feb 2024: 8. Find two totally ordered sets such that neither is isomorphic to a subset of the other.Can you find three such sets? ... Is there a countable ordinal α such thatα is the αth fixed point?

27 Oct 2023: Calculate d = (a, b) and find integers r and s such that ra sb = d when. ... iii) Find constants c and d such that λ(a, b) c log b d.

24 Jan 2024: Does 10f exist? 3. Give an example of a continuous function f : [0,) [0,), such that0f. ... Must f vanishidentically?[We say g vanishes near a and b if there exists > 0 such that g(x) = 0 for x 6(a ,b ).]. 1. 2 ANALYSIS I EXAMPLES 4.

26 Jan 2024: a2. b2. ak. bk. Example. Given a, b G,. sclG ([a, b]) 12χ. ... such thatD(φ) := sup.

24 Nov 2023: 45) Show that there is a w such that Ww = {w} and a w such that |Ww| = |w|. ... Show that the following sets arecomputably enumerable:. (a) {w ; there are three distinct words v such that f(w, v)};(b) {w ; there is a word v of even length such

10 Oct 2023: b) Now let X and Y be jointly Gaussian random vectors such that Cov(X) is positivedefinite. ... Let Q bethe equivalent probability measure such that dQ. dP eX.

28 Oct 2023: functionf : (X,w) [0, 1] such that f(p) = 1 and f = 0 on C. ... Showthat (K,M,µ1) is the completion of (K,B,µ). 19. Let X be a real or complex vector space with a topology such that addition, scalarmultiplication are continuous, and

10 Oct 2023: n such that Ax = 0.• There exists a y Rm with (AT y)i 0 for all i = 1,. , ... Make this assumption for the rest of the problem.(b) Why must there exist an equivalent measure Q such that 1.

25 Feb 2024: c) Give an example of a sequence {𝜙 𝑗}𝑗=1 𝐶𝑐 (R𝑛) such that. ... Deduce thatR𝑚𝜓(𝑦)𝑑𝑦 = 𝑢[Ψ], where Ψ(𝑥) =. R𝑚𝜙(𝑥, 𝑦)𝑑𝑦. b) Show that there exists a sequence of smooth functions 𝑓𝑛 𝐶𝑐

7 Oct 2023: g : C such that |g| = 1 |ν|-a.e. and |ν|(A) =Ag dν for all A F. ... Recall thatµ and ν2 are said to be orthogonal if there is a measurable partition = AB such thatµ(B) = |ν2|(A) = 0.].

31 Jan 2024: 8. Let t1, t2,. be propositions such that, for every valuation v, there exists n N withv(tn) = 1. ... Show that there is a proposition b, inwhich the only primitive propositions appearing are those that appear in both a and c,such that a b and b c.

17 Jan 2024: b) We say that a measurable 𝑓 : R𝑛 C is in weak-𝐿𝑝(R𝑛), written 𝑓 𝐿𝑝,𝑤 (R𝑛) if there exists aconstant 𝐶 such that. |{ ... Deduce 𝑁𝑖=1. 𝐵𝑖. 6 3𝑛 𝑘︁𝑗=1. 𝐵𝑖𝑗. b) () Suppose {𝐵 𝑗 : 𝑗

14 Nov 2023: Show that spanwB =. (B). for B X.Deduce that a w-closed subspace Y of X is a dual space: there is a normedspace Z such that Y = Z. ... Note that such a linear map is bounded.) Show that forT B(X,Y ) the following are all equivalent to T being weakly

11 Oct 2023: algebra. 1.2. Show that the following sets of subsets of R all generate the same σ-algebra:(a) {(a,b) : a < b}, (b) {(a,b] : a < b}, (c) {(,b] : b ... an,bn] such that the Lebesgue measure of A4B(= (Ac B) (ABc)) is less than ε.

17 Jul 2023: a) Show that the unique minimizer is x = 0. (b) Find constants 0 < m < M and L > 0 such that m f ′′(x) M and |f ′′′(x)| L for all x. ... Given constants b1, b2 such that b1 eb2 0 use the Lagrangian method to.

24 Nov 2023: If A is the matrix of the first of these (say), find a non-singular matrix P such that PT AP is diagonalwith entries 1. ... an be real numbers such that a1 an = 0 and a21 a2n = 1.

8 Nov 2023: 12. (a) Show that if x ̸= y are vectors in the finite dimensional vector space V , then there is a linear func-tional θ V such that θ(x) ̸= ... Let A, B V. Prove that A B if and only if Ao Bo.Show that A = V if and only if Ao = {0}.

23 Oct 2023: Show that:. (a) There is a nondeterministic automaton N with n 1 states such that L(N) = Ln and(b) if D is a deterministic automaton with fewer than 2n states, ... Prove that there is a proper excerpt e of v such that xey L.

28 Nov 2023: Operator-valued measures. A resolution of the identity of H over K is amap P : B B(H) such that. ... over K. Then there is an isometric, unital -isomorphism Φ of L(P) onto acommutative, unital C-subalgebra of B(H) such that.

11 Mar 2024: Proof 2: more words. Let ϵ > 0. Choose N N such that N > 1/ϵ2. ... f1 When f : A B is a function, and C is a subset of B, thesymbol f1(C) denotes the preimage of the set C: the set ofelements a A such

29 Sep 2023: The discriminant = (a, b)=16(4a327b2)is non-zero. Conversely, for any pair (a, b) O2K such that (a, b) , 0, the equation(2.1) defines an elliptic curve. ... ap bp = cp. to the Fermat equation in exponent p; thus a, b, c Z are coprime non-zero

10 Oct 2023: Suppose that α has minimal polynomial f over Q, and let β = α4.Find a, b, c Q such that β = a bα cα2. ... 9. Let K and L be subfields of a field M such that M/K is finite.

8 Mar 2024: αd OK such that. OK = α1Z. αdZ.Such a collection of elements α1,. , ... 14 PÉTER P. VARJÚ. of this form. So no such π1 may exist.

28 Nov 2023: ii) If A is compact and B is closed, then there exists f X such that supA f <infB f. ... An algebra norm on A is a norm ‖‖ on A such that ‖ab‖ 6 ‖a‖‖b‖ for alla,b A.

14 Sep 2023: If χ: A B is an algebra homomorphismthen there is b B such that χ(x) = bxb1 for all x A. ... Evidently such a pair is also an element of AutA(M/X/G). (b) Given a group homomorphism σ : G AutA(M/X/G) such that pr1 σ =1G, the restriction

29 Nov 2023: 10. )〉. So. R2 =〈(. 10. )〉〈(. 01. )〉is the only such decomposition in this case. ... Ws such that W = sj=1Wj. Thus. V =ri=1. Ui sj=1.

31 Jan 2024: G = H1 BH2 BH3 BH4 B BHn = {e}. such that each quotient Hi1/Hi is simple. ... Since they have the same cycle type, there is a σ Sn such that (a b c) = σ(1 2 3)σ1.

25 Oct 2023: Then there is a point y / E such. that B(y,r) E 6= whenever r > 0. ... Since Uj1 isopen we can find a δj1 > 0 with δj1 δj/4 such that B(xj1,δj1) Uj1.

25 Oct 2023: Theorem 4.2. If f : [a,b] [a,b] is a continuous function, then we canfind a w [a,b] such that f(w) = w. ... Supposethat we can find a a0 < a1 < < an b such that, writing σ = ‖fP‖we have either.

20 Dec 2023: Proposition 2.1.1. ([25, Exercise 2F]) For every ring homomorphism φ: A Band element b B such that bφ(a)φ(a)b = φ(δ(a)) for all a A, ... there is a uniquering homomorphism ψ : A[T; δ] B such that ψ|A = φ and ψ(T) = b.

31 Jan 2024: Theorem. There is no group homomorphism F : {0} Z such that the composition. ... such that. f g ' IdY f ′ g′ ' IdZ g f ' IdX g′ f ′ ' IdY.

24 Oct 2023: Vn such that V ' V1 Vn. Theorem 4.12. Suppose that G is finite and |G| 6= 0 in F. ... central character, such that z v = λ(z) v forall z Z(G) and v V.

24 Nov 2023: Let a,b K such that the polynomials f = Xm a, g = Xm b are irreducible. ... Use asuitable Lagrange resolvent to find a Q(ζ3) such that K = Q(ζ3, 3.

29 May 2024: Then there is abijection h: A B. Proof. We seek partitions A = P Q of A and B = R S of B such thatf(P) = R and g(S) = Q. ... then h is a bijection. To see that such partitions exists, let X = P(A) and define H : X X byH(P) = A g(B f(P)).

15 Apr 2024: b) Consider a polygonal decomposition of Σ such that at least three edges meet at each vertex andeach face has at least three edges. ... Deduce. that there exists δ > 0 such that in any hyperbolic triangle the union of the δ-neighbourhoods oftwo of