$\def\R{\mathbb{R}}$ $\def\C{\mathbb{C}}$ $\def\O{\Omega}$ $\def\veps{\varepsilon}$ $\def\vphi{\varphi}$ $\def\hT{\widehat{T}}$ $\def\Tkple{\mathcal{T}_{k+1}}$ $\newcommand{norm}[1]{\|#1\|}$ $\newcommand{abs}[1]{|#1|}$ $\newcommand{unitinterval}{[0,1]}$
The following list of corrections is updated occasionally and ordered chronologically. Important changes are marked by an exclamation mark. Letters t,m,b refer top, middle, and bottom parts of a page.
Last update: March 9, 2021
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | 6m | Remove subscript $x$ in identities for difference quotients (3 times); replace $x$ by $x_j$ (3 times) in formula following This implies that | |
2 | ! | 14m | Remove factor $\Delta x$ in denominator of identity for $\norm{V}$ |
3 | 24t | Change: ... is regular with eigenvalues $\lambda_j \ge 1$, $j=1,2,\dots,J-1$, and ... | |
4 | 29t | Change: ... that $f(z) \ge -1$ to deduce $\abs{f(z)} \le 1$, i.e., ... | |
5 | 37m | Replace plus by minus sign in formula $3/4+\abs{x}/2$ | |
6 | ! | 56m | Remove minus sign in identity $Lu = -\Delta ...$ |
7 | ! | 61b | Replace $A$ by $-A$ in the equation of Example 1.14 |
8 | 34-35 | Improved derivation of the wave equation: wave_equation.pdf (V. 7.11.2018) | |
9 | 22t | Replace U(k+1,J+1) by U(k+2,J+1) in line 17 of code explicit_euler.m | |
10 | ! | 29m | Remove factor $\Delta x$ in sum. |
11 | 32b | According to the Gerschgorin theorem the eigenvalues of $\widetilde{A}$ are bounded from below by one. | |
12 | 36m | Add remark: We will see that the wave speed is given by $c = (\sigma/\varrho)^{1/2}$ so that to double the frequency of a vibrating string we have to divide its weight or increase its tension by 4. | |
13 | ! | 42t,m | Correct: ... if the complex eigenvalues of the matrices $A_p$ are distinct and bounded by one and Since $z_1z_2 =1$ a sufficient condition for $z_1\neq z_2$ and $\abs{z_{1,2}}\le 1$ is that $\abs{\gamma_p}<1$. Correct also: $-1 < \cos(\pi p \Delta x) < 1$ and $\abs{z_{1,2}}\le 1$ |
14 | 51 | Add: If $u\in C^4(\overline{\O})$ then we have the estimate ... in Proposition 1.17 | |
15 | 14m/15t | Add subscript $\Delta t$ in $\abs{\widetilde{E}(\xi)}$ (three times) | |
16 | 16m | Correct $\pi r^2 ... =-\kappa \partial_x u(t,x_2)-...$ | |
17 | 44m | Last sum should begin with summation index $j=1$ | |
18 | 48t | Alternatively, one may use that the integral mean of $u$ over $\partial B_r(x_0)$ equals the constant function $\varphi(r) = c_d \int_{\partial B_1(0)} u(x_0+r z) dz$ | |
19 | 48m | Replace cancelling factors $a^2$ by $r^2$ in formula following to obtain | |
20 | 51m | Condition $u\in C^4(\overline{\Omega})$ should be added in Prop. 1.17, replace $u_{j,m}$ by $u(x_{j,m})$ and $U(x_{j,m})$ by $U_{j,m}$ in the proof | |
21 | 56m | The function $G$ maps into $\R$, the identity $G(u)=Mu-\ell$ should be replaced by $G(z,u(z),...) = Mu(z) -\ell(z)$ |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | 67b | Replace $v\in C(\overline{\O})$ by $v\in C^1(\overline{\O})$ | |
2 | 81b | Change: Let $\O\subset \R^d$ be bounded, $u\in L^p(\O)$, and ... | |
3 | 93m | Add: If $a$ is symmetric then the factor $k_a/\alpha$ can be replaced by its square root. | |
4 | ! | 95t | Remove minus sign in front of boundary integral; replace Proof by Proof (sketched) |
5 | ! | 95m | Add We incorporate the result that because of the convexity of $\O$ smooth functions are dense in the set $V$ of all functions $v \in H^1_0(\O)$ sucht that $-\Delta v\in L^2(\O)$ with respect to the norm $v \mapsto \norm{\nabla v} + \norm{\Delta v}$, cf. [5]. |
6 | 70 | Add ... called a scalar or inner product ... in Definition 2.3 (i). | |
7 | 71m | Add: By the parallelogram identity $2 \norm{x}^2 + 2 \norm{y}^2 = \norm{x-y}^2 + \norm{x+y}^2$ we have that ... | |
8 | 72t | Replace $r$ by $z$ and use that $u-z\in U$ | |
9 | 95-96 | Replace $x'$ by $z'$ (five times) | |
10 | 69t | Replace $u$ by $v$ in identity for $I(v)$ | |
11 | 73b | Add to Prop. 2.5: A bounded linear operator $\tilde{A}:\tilde{V}\to W$ defined on a dense subspace $\tilde{V} \subset V$ can be uniquely extended to a bounded linear operator on $V$. | |
12 | 80m | Correct: we define the vertical average $f_k(x')= ...$ and note | |
13 | 82t | For proving statement (iii), Lusin's theorem is used | |
14 | 82m | Add: ... that the integration-by-parts formula ... holds for all ... | |
15 | 88m | Replace $C_P$ by $c_P$ once | |
16 | 96m | Replace The second equation then leads to by while the second equation simplifies to | |
17 | 96b | Add to Rem. 2.17: The example $u(r,\phi) = r^{\pi/\gamma} \sin(\phi \pi/\gamma)$ from Prop. 2.1 shows that the result is sharp; $H^2$ regularity of a boundary value problem is a stronger requirement than the condition that solutions satisfy $u\in H^2(\Omega)$. |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | ! | 106b | Replace factor $h_T^{-k}$ by $h_T^k$ in Proposition 3.3 |
2 | 108m | Item (v): Replace first integration domain by $T$ and second by $\hT$ in first formula and first integration domain by $\hT$ in second formula | |
3 | 108b | Change $\chi$ to $\widehat{\chi}$ | |
4 | ! | 111t | Replace $C^{m-1}$ by $C^r$ and correct $0\le k\le \min\mbox{{$r+1,m$}}$ |
5 | 116b | Change $A^{-1} = (I-M)^{-1} D^{-1}$ | |
6 | 118m | Add: Assume $u_h\in V_h$ is such that $a_h(u_h,v_h) = \ell(v_h)$ for all $v_h\in V_h$. | |
7 | 131 | Replace variables (nS,idx_Bdy,newCoord) by (nEdges,idxBdy,newCoords) | |
8 | 151m | Use command "m_lumped = spdiags(m_lumped_diag,0,nC,nC);" | |
9 | 103b | Add: By integrating the gradient field $w=(w_1,w_2,\dots,w_d)$ along appropriate paths ... | |
10 | 117 | Add: , i.e., the minimum is attained on the boundary. at end of Proposition 3.5 | |
11 | 118 | Replace $c>0$ by $c_{SL}>0$ in Proposition 3.6 | |
12 | ! | 118b | The estimate for the $\abs{\ell(v_h)-\ell(v_h)}$ is suboptimal; a better result is provided in the pdf file quadrature.pdf |
13 | ! | 122b | Remove squares of first two norms |
14 | ! | 144 | Add prefactor $\tau$ to the sum in Proposition 3.13, replace factors $ch^2$ and $c\tau$ by $c\tau^{-1/2}h^2$ and $\tau^{1/2}$, respectively, and terms $u_t$ and $u_{tt}$ by $\partial_t u$ and $\partial_t^2 u$, respectively, in the proof |
15 | 140,145 | The solutions should be sought on the closed time interval $[0,T]$ in Definitions 3.13 and 3.15 | |
16 | 107b | Add subscript $T$ in $\Phi$ twice | |
17 | 109m | Correct $\widehat{v} = v \circ \Phi_T \in W^{m,p}(\widehat{T})$ and $\abs{\widehat{v}}_{W^{m,p}(\widehat{T})}$ | |
18 | 106t | Replace $R$ by $R+1$ in estimate for $\abs{F(v)}$ | |
19 | 111t | The estimate follows from Proposition 3.3 by summing over all elements $T\in \mathcal{T}_h$. | |
20 | 99b | A line break should be introduced before The integer ... | |
21 | 100t | The functional $\chi_T$ should be placed in parantheses | |
22 | 103t | Remove power $p$ in $W^{m,p}$ norm of $v$ | |
23 | 107b | Remove last equal term in equation for $\nabla w$ | |
24 | 108t | Include strict lower bound for $\varrho_{\hat{T}}$ | |
25 | ! | 108m | Replace $T$ by $\hat{T}$ in final upper bound of (v), in addition to Nr. 2 above |
26 | 109t | Replace $P_T$ by $\mathcal{P}_T$ | |
27 | 121b | Replace $f$ by $\tilde{f}$ in discrete weak formulation | |
28 | ! | 122b | Replace integration domains $\Omega \setminus \Omega_h$ by $\Omega_h \setminus \Omega$ three times |
29 | ! | 124m | Correct: Otherwise, if $p>r$ use the monotonicity property of the $\ell^p$ norm $\norm{x}_p \le \norm{x}_r$ for every ... |
30 | 126b | Correct $\Gamma_D = \unitinterval \times {0}$ in Fig. 3.10 | |
31 | 136b | Equivalently, we have $v_h \circ \psi_T \in \mathcal{P}_2(T)$ for all $T\in \mathcal{T}_h$ | |
32 | 137t | The second equality sign should be replaced by the approximation symbol $\approx$ | |
33 | 144m | The first displayed formula in the proof should be replaced by the representation $(d_t Q_h u(t_k)-\partial_t u(t_k),v_h)$ of the consistency term | |
34 | 147m | In the estimate of Prop. 3.16 the maximum over $k=1,...,K$ should be considered |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | 206 | Correct author name of Reference 22: Praetorius, D. | |
2 | 155m | Add: solution of the Poisson problem with vanishing right-hand side | |
3 | 159m | Correct: is positive if $\alpha \neq 0$ | |
4 | ! | 162b | The patch $\omega_z$ should be the interior of the support, i.e., $\omega_z = {\rm int}\,{\rm supp} \, \vphi_z$ |
5 | 169m | Add in Def. 4.6: $f\in L^2(\O)$ | |
6 | ! | 172b | Correct in Lemma 4.3: ${\rm supp}\, b_T = T$ and ${\rm supp}\, b_S = \overline{\omega}_S$ |
7 | 182 | Throughout Section 4.3 the index $k$ belongs to $\mathbb{N}_0$ | |
8 | ! | 182b | Correct: if every $T\in \mathcal{T}_k$ is the union of elements in $\Tkple$ |
9 | 188m | Note that $\delta_{k+1}$ vanishes on $\partial \O$; for the definition of the Scott-Zhang interpolant on $\O_i$ we assume that sides $S_z$ associated with $z\in \partial \O_i$ also belong to $\partial \O_i$ | |
10 | ! | 189b | Change $2^{-1/2}$ to $2^{-1/d}$ and replace $\sqrt{2}$ and $2^{1/2}$ by $2^{1/d}$ throughout Subsection 4.3.4 |
11 | 192t | The sum is over elements $T'\in \mathcal{T}_{k+1}$ with $T'\subset \overline{\O \setminus \cup \mathcal{M}_k}$ | |
12 | ! | 193b | Replace exponent $-d/s$ by $-d/(2s)$ |
13 | 194m | Add factor $c_{{\rm card}}$ after second inequality and replace $c_{qo}$ by $\widetilde{c}_{qo}$ | |
14 | 196b | Use $\veps = \widetilde{q} \norm{\nabla (u-u_k)}$ and note that $e_k \approx \norm{\nabla(u-u_k)}$ | |
15 | 201m | Add in initialization of Alg. 4.4: set $\mathcal{T}^1= \mathcal{T}^0$ and $j=1$; the stopping criterion in Step (3) should require that $\eta_{{\rm temp}}^j \le \veps$; the otherwise case in Step 4 should set $\mathcal{T}^j = \mathcal{T}^{j-1}$ | |
16 | 204t | Replace the abstract theorem by Proposition 4.5 and bounds for $u-\widetilde{u}$ by $\widetilde{u}-U$; add noting that $-\Delta \partial_t \widetilde{u} = -\Delta_h \partial_t U$ | |
17 | 205m | Replace the abstract error estimate by Proposition 4.5 | |
18 | ! | 169t | The convergence $\mathcal{J}_h v \to v$ is in $L^2(\Omega)$ |
19 | 170/171 | Replace square brackets $[..]$ by double square brackets denoting jumps three times | |
20 | 172t | Correct: *The jumps of $\nabla u_h$ are a measure of nonsmoothness of $u_h$ * | |
21 | 174t | Replace square brackets $[..]$ by double square brackets denoting jumps twice | |
22 | 178m | Here, $\varrho_z$ is the height of the element with respect to the side $S_z$ | |
23 | ! | 179b | Add square to factor $f(..)$ in formula for $\eta_T$; remove factor $h_T^{(2-d)/2}$ in formula for $\eta_S$ |
24 | 186m/b | Replace $h_{S_z}$ by $h_z$ and remove second power $\ell$ in term $\nabla^\ell \varphi_z^\ell$ | |
25 | 187t | Exchange order of last two terms in right-hand side of first bound | |
26 | 188m | Remove fullstop in front of and note | |
27 | ! | 189t | Remove minus sign in front of last sum |
28 | 191t | Replace square brackets $[..]$ by double square brackets denoting jumps once |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | 210 | Add in Remark 5.1: This follows from the explicit characterization of eigenfunctions of the discretized Laplace operator on uniform grids, cf. Lemma 1.1 in Chapter 1. | |
2 | 219m | Correct sign in exponent: $2^{\ell d} = n_L 2^{(\ell-L)d}$, analogously in sum below | |
3 | 224b | Replace $v\in H^1_0(\O_1)$ by $v\in H^1_{\Gamma_1}(\O_1)$ | |
4 | 227t | Add lower bound: $0<\theta<\theta* = ...$ | |
5 | 230m | Add lower bound: $\norm{\nabla v} \le \norm{\nabla v_1}_{L^2(\O_1)} +\, ... $ | |
6 | 235m | A simpler derivation considers the eigenvalues of $C^{1/2}A C^{T/2}$ via a standard (euclidean) Rayleigh quotient and the transformation $v=C^{T/2} w$ | |
7 | 237t | Note that the right-hand side of the estimate is bounded by $c h \norm{\nabla v_h}$ | |
8 | 243t | The case that $\mathcal{T}_H$ has no free nodes formally corresponds to an infinite mesh size $H = \infty$ | |
9 | 216t | Correct Computing |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | 251m | Add in Remark 6.2 (ii): ... $ \norm{Mx} \ge \gamma \norm{x}_\ell$ for all $x\in \R^n$, i.e., $M$ is injective, hence regular, and to ... | |
2 | 253m | Add: and analogously, noting $B_K=0$,... and $B^Ts = [0,B_I^Ts]^T\equiv B_I^Ts \in \text{Im} B^T$ | |
3 | ! | 253b | Exchange first and second conditions and enumerate them. |
4 | 265b | Add in Theorem 6.4: ... if and only if $a$ is coercive on $\text{ker}B= \text{{$v\in V: b(v,q) = 0 \text{ f.a. }q\in Q$}}$ | |
5 | 267 | Correct: ... let $u\in \text{ker}B \setminus \text{{0}}$; change With $p=0$ we have that $(u,p)=L^{-1}(\ell,0), i.e., ...$ correct $\sup_{v\in V\setminus \text{{0}}}$ after show that | |
6 | 274m | Change: In fact, a simpler error estimate that resembles the classical Cea lemma can be proved if ... | |
7 | ! | 274b | Insert condition ${q_h}\rvert_{\partial \Omega} = 0$ in definition of $Q_h$ |
8 | ! | 276m | Delete such that there exist $v\in V$ and $q_h\in Q_h$ with $b(v,q_h)\neq0$ and and nontrivial |
9 | 279t | Add remark: Note that $v_h \mapsto \norm{Bv_h}_Q$ defines a norm on $V_h$ so that $\norm{B v_h}_Q \le c_h \norm{v_h}$, where $c_h$ depends on the dimension of $V_h$ | |
10 | 279m | Add: ... we expect $\sigma = 1$ since $\norm{\text{div} I_h v} \le c h \norm{D^2 v}$ for every smooth divergence-free vector field $v$ on $\Omega$ | |
11 | 273t | Add subindex $X$ to norm $\norm{x-w_h}$ | |
12 | 274t | The part of Theorem 6.7 beginning with Then for every ... should not be indented | |
13 | 276m | The subspaces $V_h$ and $Q_h$ should be closed |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | ! | 317 | Corrections in lines 21, 36, 45 of code "stokes_cr", see file stokes_cr_corr.m |
2 | 284m | Correct Remarks 7.1 (ii): The set $C^\infty(\overline{\Omega};\R^d)$ is dense in $H(\text{div};\Omega)$. | |
3 | 286b | Replace factor $(1+c_P^2)$ by $(1+c_P^2)^{1/2}$ twice | |
4 | 288b | Insert: But then $u_h(x) \cdot n_{S_{d+1}} = d_T (x-z_{d+1}) \cdot n_{S_{d+1}} = 0$ for every ... | |
5 | 289m | Replace $x\in T_+\cup T_-$ by $x\in \Omega$ | |
6 | 290m | Add: ... has to be used which maps normals to normals. | |
7 | 292m | Replace ... allows us to prove ... by ... allows us to deduce ... | |
8 | 293m | Add comment: The smallness condition on $h$ cannot be avoided in general; for $h$ sufficiently small we have that the number of sides dominates the number of elements in $\mathcal{T}_h$. | |
9 | 293m | Replace $v_h$ by $-v_h$ in Rem. 7.6 | |
10 | 294t | Replace $H^1(T)$ by $H^1(T;\R^d)$ twice | |
11 | 295b | Add in Rem. 7.2 (ii): ... provided that the additional regularity condition $g\in H^1(\Omega)$ is satisfied. | |
12 | 305t | Proof of the discrete inf-sup condition for the Taylor-Hood element: taylor_hood.pdf | |
13 | 305m | Lemma 7.3: Add There exists $\beta'>0$ such that for all $q_h \in Q_h$ we have ...; define $w_z = 0$ for $z\in \Gamma_D = \partial \Omega$ | |
14 | 307b | Delete unnecessary brackets $(\beta'...)$ and incorrect term $-\mu \norm{\nabla u_h} \norm{p_h}_{L^2(\Omega)}$ | |
15 | 309t | Change second sentence in Rem. 7.10 (ii): Here, we use a special bilinear form $c_h$ and are able to avoid an inf-sup condition for $b$. | |
16 | 311b | Write $b_h$ instead of $b$ for discretized bilinear form | |
17 | 312b | Correct: Since $I_F$ reproduces constants we may replace $v$ by $v-\overline{v}_T$ ... | |
18 | 324m | Insert: ... and in case that $\Gamma_N$ is empty in fact ... | |
19 | 328b | Correct: Applying Gauss's theorem on inner sets $\Omega_j$ or imposing $q(u)\cdot n = 0$ on $\partial \O \cap \partial \O_j$ yields that ... | |
20 | 334m | Insert dots for scalar products with vector $n_S$ twice | |
21 | 343b | Move factor $d$ inside brackets in front of Kronecker symbol $\delta_{mn}$ | |
22 | ! | 289m | Replace factor $d!$ by $d$ in formula for $\delta_{S,T}$ |
23 | 316b | The loop over $k$ is misleading and should be removed, replace factor $1/d$ by $1$ |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | 403 | Add reference M. Costabel, A coercive bilinear form for Maxwell’s equations, Journal of Mathematical Analysis and Applications, 157 (1991), 527–541. | |
2 | 349m | Correct: ... two nearby material points ... | |
3 | 354t | Modify: then we obtain robust approximation results in the relative error for the limit $\lambda \to \infty$ | |
4 | 356m | Add in Rem. 8.4: which is equivalent to $\int_\O \mathbb{C} \veps_{\mathcal{T}} (u_h) : \veps_{\mathcal{T}} (v_h) dx = \ell(v_h)$ | |
5 | 358t | Correct: $a_h(u,v_h) = \sum_{T\in \mathcal{T}_h} \int_T \mathbb{C} \veps(u): \nabla v_h d x$ | |
6 | 358t | Correct two signs: $... = \int_\O f\cdot v_h dx + \int_{\Gamma_N} g \cdot v_h ds - \sum ...$ | |
7 | 356m | The condition $\lambda \ge 1$ should be added to Prop. 8.2 | |
8 | 357m | The triple bar expression is a norm provided $\Gamma_D$ contains at least two sides $S\in \mathcal{S}_h$ | |
9 | 357b | It is assumed that $\beta_S \ge 2\mu$ in Lemma 8.3 | |
10 | ! | 358t | All minus signs in final right-hand side of the identities for $a_h(u_h,v_h)$ should be changed to plus signs (see also Nr. 6) |
11 | 359t | Sides belonging to $\overline{\Gamma}_N$ should not be included in the last sum | |
12 | 359m | Remove factor $\beta_S$ in front of $h_T^2$ | |
13 | ! | 362t | Replace factor $d!$ by $d$ in formula for $vol_S$ |
14 | 363t/m | Add in captions of Fig. 8.5 and Fig. 8.6 that solutions of the Navier-Lame equations are approximated |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | ! | 406 | A.1.6: add factor $1/2$ to right-hand side |
2 | ! | 407 | A.1.8: correct $\phi_\ell(x) = e^{i\ell x}$ |
3 | ! | 410 | A.1.21: replace $a_n$ and $b_n$ by $\alpha_n$ and $\beta_n$ |
4 | ! | 412 | A.1.28: correct right-hand side $\frac12 \partial_t^-(\partial_t^+ U_j^k)^2$ |
5 | ! | 422 | A.2.1: replace term $r^{-1} \widetilde{u}(r,\phi)$ by $r^{-1} \partial_r \widetilde{u}(r,\phi)$ in formula for $\Delta u(r,\phi)$ |
6 | ! | 429 | A.2.33: remove factors $1/N$ (twice) |
7 | ! | 438 | A.3.26: where $\varrho_j>0$ is the inverse of the height of $T$ ... |
8 | ! | 407 | A.1.8.: Assume that $f=\sum_{\ell\in \mathbb{Z}} f_\ell \phi_\ell$ in second part of (ii) |
9 | 411 | A.1.26: Hint: Use that the spectral radius is a sharp lower bound for operator norms | |
10 | ! | 420 | A.1.5: Correct $c = (\sigma/\varrho)^{1/2}$ and use the cosine transform to compute the coefficients $\alpha_m$ |
11 | ! | 421 | A.1.8: Correct density $\varrho = 1.2041\, {\rm kg/m^3}$ |
12 | ! | 443 | A.3.8: Correct density $\varrho = 1.009\cdot 10^3 \, {\rm kg/m^3}$ |
13 | ! | 444 | A.4.2: Move minus sign from second entry of second row to first entry of second row in matrix |
14 | 450 | A.4.32: Add: for sufficiently regular weak solutions | |
15 | 450 | A.4.33: Add $\frac12 \norm{\nabla U^0}^2$ to right-hand side in part (ii) | |
16 | 457 | A.5.12: Correct: $1/2< a< 1$ |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | 509 | Add command "d_fac = factorial(d)" in function "nodal_basis" and correct identity for "Vol_T(j)" to improve performance |
Nr. | Imp. | Page(s) | Correction |
---|---|---|---|
1 | iv | Correct Universität |
Thanks for valuable hints to: D. Gallistl, L. Minden, C. Palus, G. Dolzmann