THINKING MATHEMATICALLY W/ACCESS
19th Edition
ISBN: 9780135323038
Author: Blitzer
Publisher: Pearson Custom Publishing
expand_more
expand_more
format_list_bulleted
Question
Chapter 14.1, Problem 7CVC
To determine
Whether the statement “An edge can be a part of a path only once.”
is true or false.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
Help me with the accurate answer and solution asap pls pls thank yo u
Pls help me with accurate answer and solution as soon as possible pls
thank you
Help me with step by step solution and accurate answer as soon as possible pls
Chapter 14 Solutions
THINKING MATHEMATICALLY W/ACCESS
Ch. 14.1 - CHECK POINT 1 Explain why Figures 14.4(a) and (b)...Ch. 14.1 - CHECK POINT 2 The city of Metroville is located on...Ch. 14.1 - Prob. 3CPCh. 14.1 - CHECK POINT 4 The floor plan of a four-room house...Ch. 14.1 - CHECK POINT 5 A security guard needs to walk the...Ch. 14.1 - CHECK POINT 6 List the pairs of adjacent vertices...Ch. 14.1 - Fill in each blank so that the resulting statement...Ch. 14.1 - Fill in each blank so that the resulting statement...Ch. 14.1 - Fill in each blank so that the resulting statement...Ch. 14.1 - Fill in each blank so that the resulting statement...
Ch. 14.1 - Prob. 5CVCCh. 14.1 - Fill in each blank so that the resulting statement...Ch. 14.1 - Prob. 7CVCCh. 14.1 - Fill in each blank so that the resulting statement...Ch. 14.1 - Fill in each blank so that the resulting statement...Ch. 14.1 - The graph models the baseball schedule for a week....Ch. 14.1 - The graph models the baseball schedule for a week....Ch. 14.1 - The graph models the baseball schedule for a week....Ch. 14.1 - The graph models the baseball schedule for a week....Ch. 14.1 - Prob. 5ECh. 14.1 - Prob. 6ECh. 14.1 - In Exercises 7-8, explain why the two figures show...Ch. 14.1 - In Exercises 7-8, explain why the two figures show...Ch. 14.1 - Eight students form a math homework group. The...Ch. 14.1 - Prob. 10ECh. 14.1 - Prob. 11ECh. 14.1 - In Exercises 11-12, draw a graph that models the...Ch. 14.1 - In Exercises 13-14, create a graph that models the...Ch. 14.1 - In Exercises 13-14, create a graph that models the...Ch. 14.1 - In Exercises 15-18, draw a graph that models (he...Ch. 14.1 - In Exercises 15-18, draw a graph that models (he...Ch. 14.1 - In Exercises 15-18, draw a graph that models the...Ch. 14.1 - In Exercises 15-18, draw a graph that models the...Ch. 14.1 - In Exercises 19-20, a security guard needs to walk...Ch. 14.1 - In Exercises 19-20, a security guard needs to walk...Ch. 14.1 - In Exercises 21-22, a mail carrier is to walk the...Ch. 14.1 - In Exercises 21-22, a mail carrier is to walk the...Ch. 14.1 - In Exercises 23-33, use the following graph. Find...Ch. 14.1 - In Exercises 23-33, use the following graph....Ch. 14.1 - In Exercises 23-33, use the following graph. Which...Ch. 14.1 - In Exercises 23-33, use the following graph.
26....Ch. 14.1 - In Exercises 23-33, use the following graph.
27....Ch. 14.1 - In Exercises 23-33, use the following graph. Use...Ch. 14.1 - Prob. 29ECh. 14.1 - Prob. 30ECh. 14.1 - Prob. 31ECh. 14.1 - In Exercises 23-33, use the following...Ch. 14.1 - Prob. 33ECh. 14.1 - Prob. 34ECh. 14.1 - In Exercises 34-48, use the following...Ch. 14.1 - In Exercises 34-48, use the following graph. Which...Ch. 14.1 - In Exercises 34-48, use the following graph. Which...Ch. 14.1 - In Exercises 34-48, use the following graph. Use...Ch. 14.1 - In Exercises 34-48, use the following...Ch. 14.1 - In Exercises 34-48, use the following graph. Use...Ch. 14.1 - Prob. 41ECh. 14.1 - Prob. 42ECh. 14.1 - In Exercises 34-48, use the following...Ch. 14.1 - In Exercises 34-48, use the following graph,...Ch. 14.1 - In Exercises 34-48, use the fallowing graph....Ch. 14.1 - Prob. 46ECh. 14.1 - Prob. 47ECh. 14.1 - In Exercises 34-48, use the following graph....Ch. 14.1 - Prob. 49ECh. 14.1 - In Exercises 49-52, draw a graph with the given...Ch. 14.1 - In Exercises 49-52, draw a graph with the given...Ch. 14.1 - In Exercises 49-52, draw a graph with the given...Ch. 14.1 - Prob. 53ECh. 14.1 - Prob. 54ECh. 14.1 - What are equivalent graphs?Ch. 14.1 - Prob. 56ECh. 14.1 - Prob. 57ECh. 14.1 - Prob. 58ECh. 14.1 - Prob. 59ECh. 14.1 - Prob. 60ECh. 14.1 - Prob. 61ECh. 14.1 - Prob. 62ECh. 14.1 - Prob. 63ECh. 14.1 - Prob. 64ECh. 14.1 - Prob. 65ECh. 14.1 - Make Sense? In Exercises dd-d9, determine whether...Ch. 14.1 - Make Sense? In Exercises dd-d9, determine whether...Ch. 14.1 - Prob. 68ECh. 14.1 - Prob. 69ECh. 14.1 - Prob. 70ECh. 14.1 - Use the information in Exercise 10 to draw a graph...Ch. 14.1 - Prob. 72ECh. 14.1 - Prob. 73ECh. 14.1 - Prob. 74ECh. 14.2 - CHECK POINT I Refer to the graph in Figure 1423....Ch. 14.2 - Prob. 2CPCh. 14.2 - Prob. 3CPCh. 14.2 - Prob. 4CPCh. 14.2 - Prob. 1CVCCh. 14.2 - Prob. 2CVCCh. 14.2 - Prob. 3CVCCh. 14.2 - Fill in each blank so that the resulting statement...Ch. 14.2 - Fill in each blank so that the resulting statement...Ch. 14.2 - Prob. 6CVCCh. 14.2 - Fill in each blank so that the resulting statement...Ch. 14.2 - Prob. 8CVCCh. 14.2 - Prob. 9CVCCh. 14.2 - Prob. 10CVCCh. 14.2 - Prob. 1ECh. 14.2 - Prob. 2ECh. 14.2 - Prob. 3ECh. 14.2 - In Exercises 1-6, use the graph shown. In each...Ch. 14.2 - Prob. 5ECh. 14.2 - Prob. 6ECh. 14.2 - Prob. 7ECh. 14.2 - In Exercises 7-8, a graph is given. a. Explain why...Ch. 14.2 - Prob. 9ECh. 14.2 - Prob. 10ECh. 14.2 - Prob. 11ECh. 14.2 - In Exercises 11-12, a graph is given. Explain why...Ch. 14.2 - In Exercises 13-18, a connected graph is...Ch. 14.2 - In Exercises 13-18, a connected graph is...Ch. 14.2 - Prob. 15ECh. 14.2 - In Exercises 13-18, a connected graph is...Ch. 14.2 - Prob. 17ECh. 14.2 - In Exercises 13-18, a connected graph is...Ch. 14.2 - Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given. a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given. a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given. a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given. a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given. a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 19-32, a graph is given.
a. Determine...Ch. 14.2 - In Exercises 33-36, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 33-36, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 33-36, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 33-36, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 37-40, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 37-40, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 37-40, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 37-40, use Fleury’s Algorithm to find...Ch. 14.2 - In Exercises 41-44, a graph is given. a. Modify...Ch. 14.2 - In Exercises 41-44, a graph is given. a. Modify...Ch. 14.2 - In Exercises 41-44, a graph is given.
a. Modify...Ch. 14.2 - In Exercises 41-44, a graph is given.
a. Modify...Ch. 14.2 - Prob. 45ECh. 14.2 - In Exercises 45-18, we revisit the four-block;...Ch. 14.2 - Prob. 47ECh. 14.2 - In Exercises 45-48, we revisit the four-block,...Ch. 14.2 - Prob. 49ECh. 14.2 - Prob. 50ECh. 14.2 - In Exercises 51-52, the layout of a city with land...Ch. 14.2 - In Exercises 51-52, the layout of a city with land...Ch. 14.2 - Prob. 53ECh. 14.2 - In Exercises 54-55, a floor plan is shown.
a. Draw...Ch. 14.2 - In Exercises 54-55, a floor plan is shown.
a. Draw...Ch. 14.2 - Prob. 56ECh. 14.2 - Prob. 57ECh. 14.2 - Prob. 58ECh. 14.2 - Prob. 59ECh. 14.2 - In Exercises 50-60, a map is shown. a. Draw a...Ch. 14.2 - Prob. 61ECh. 14.2 - Prob. 62ECh. 14.2 - Prob. 63ECh. 14.2 - Prob. 64ECh. 14.2 - Prob. 65ECh. 14.2 - Prob. 66ECh. 14.2 - Prob. 67ECh. 14.2 - Prob. 68ECh. 14.2 - Make Sense? In Exercises 69-72, determine whether...Ch. 14.2 - Prob. 70ECh. 14.2 - Prob. 71ECh. 14.2 - Make Sense? Zn Exerciser 69-72, determine whether...Ch. 14.2 - Prob. 73ECh. 14.2 - Prob. 74ECh. 14.2 - Prob. 75ECh. 14.3 - CHECK POINT I a. Find a Hamilton path that begins...Ch. 14.3 - Prob. 2CPCh. 14.3 - CHECK POINT 3 Use the weighted graph in Figure...Ch. 14.3 - Prob. 4CPCh. 14.3 - Prob. 5CPCh. 14.3 - Prob. 1CVCCh. 14.3 - Prob. 2CVCCh. 14.3 - Fill in each blank so that the resulting statement...Ch. 14.3 - Prob. 4CVCCh. 14.3 - Fill in each blank so that the resulting statement...Ch. 14.3 - Fill in each blank so that the resulting statement...Ch. 14.3 - Prob. 7CVCCh. 14.3 - Prob. 8CVCCh. 14.3 - Prob. 1ECh. 14.3 - In Exercises 1-4, use the graph shown.
2. Find a...Ch. 14.3 - Prob. 3ECh. 14.3 - In Exercises 1-4, use the graph shown.
4. Find a...Ch. 14.3 - Prob. 5ECh. 14.3 - In Exercises 5-8, use the graph shown.
6. Find a...Ch. 14.3 - Prob. 7ECh. 14.3 - In Exercises 5-8, use the graph shown. Find a...Ch. 14.3 - For each graph in Exercises 9-14, a. Determine if...Ch. 14.3 - For each graph in Exercises 9-4, a. Determine if...Ch. 14.3 - For each graph in Exercises 9-14, a. Determine if...Ch. 14.3 - For each graph in Exercises 9-14,
a. Determine if...Ch. 14.3 - For each graph in Exercises 9-14,
a. Determine if...Ch. 14.3 - For each graph in Exercises 9-14, a. Determine if...Ch. 14.3 - In Exercises 15-18, determine the number of...Ch. 14.3 - In Exercises 15-18, determine the number of...Ch. 14.3 - In Exercises 15-18, determine the number of...Ch. 14.3 - In Exercises 15-18, determine the number of...Ch. 14.3 - In Exercises 19-24, use the complete, weighted...Ch. 14.3 - In Exercises 19-24, use the complete, weighted...Ch. 14.3 - In Exercises 19-24, use the complete, weighted...Ch. 14.3 - In Exercises 19-24, use the comple\te, weighted...Ch. 14.3 - In Exercises 19-24, use the complete, weighted...Ch. 14.3 - In Exercises 19-24, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - In Exercises 25-34, use the complete, weighted...Ch. 14.3 - Practice Plus
In Exercises 35-38, a graph is...Ch. 14.3 - Practice Plus
In Exercises 35-3S, a graph is...Ch. 14.3 - Practice Plus
In Exercises 35-38, a graph is...Ch. 14.3 - Practice Plus In Exercises 35-38, a graph is...Ch. 14.3 - Application Exercises In Exercises 39-40, a sales...Ch. 14.3 - Prob. 40ECh. 14.3 - Use the map to fill in the three missing weights...Ch. 14.3 - Prob. 42ECh. 14.3 - Using the Brute Force Method, the optimal solution...Ch. 14.3 - 44. Use the Nearest Neighbor Method to find an...Ch. 14.3 - In Exercises 45-47, you have three errands to run...Ch. 14.3 - In Exercises 45-47, you have three errands to run...Ch. 14.3 - Prob. 47ECh. 14.3 - Prob. 48ECh. 14.3 - Prob. 49ECh. 14.3 - Prob. 50ECh. 14.3 - Prob. 51ECh. 14.3 - Prob. 52ECh. 14.3 - Prob. 53ECh. 14.3 - Prob. 54ECh. 14.3 - Prob. 55ECh. 14.3 - 56. Why is the Brute Force Method impractical for...Ch. 14.3 - Prob. 57ECh. 14.3 - Prob. 58ECh. 14.3 - 59. An efficient solution for solving traveling...Ch. 14.3 - Make Sense? In Exercises60-63, determine whether...Ch. 14.3 - Prob. 61ECh. 14.3 - Prob. 62ECh. 14.3 - Make Sense? In Exercises 60-63, determine whether...Ch. 14.3 - Prob. 64ECh. 14.3 - Ambassadors from countries A, B, C, D, E, and F...Ch. 14.3 - 66. In this group exercise, you will create and...Ch. 14.4 - CHECK POINT I Which graph in Figure 14.51 is a...Ch. 14.4 - Prob. 2CPCh. 14.4 - Prob. 3CPCh. 14.4 - Prob. 1CVCCh. 14.4 - Prob. 2CVCCh. 14.4 - Prob. 3CVCCh. 14.4 - Prob. 4CVCCh. 14.4 - Prob. 5CVCCh. 14.4 - Prob. 6CVCCh. 14.4 - Prob. 1ECh. 14.4 - Prob. 2ECh. 14.4 - Prob. 3ECh. 14.4 - Prob. 4ECh. 14.4 - Prob. 5ECh. 14.4 - Prob. 6ECh. 14.4 - Prob. 7ECh. 14.4 - Prob. 8ECh. 14.4 - Prob. 9ECh. 14.4 - Prob. 10ECh. 14.4 - Prob. 11ECh. 14.4 - Prob. 12ECh. 14.4 - Prob. 13ECh. 14.4 - Prob. 14ECh. 14.4 - Prob. 15ECh. 14.4 - Prob. 16ECh. 14.4 - Prob. 17ECh. 14.4 - Prob. 18ECh. 14.4 - Prob. 19ECh. 14.4 - Prob. 20ECh. 14.4 - Prob. 21ECh. 14.4 - Prob. 22ECh. 14.4 - Prob. 23ECh. 14.4 - Prob. 24ECh. 14.4 - Prob. 25ECh. 14.4 - Prob. 26ECh. 14.4 - Prob. 27ECh. 14.4 - Prob. 28ECh. 14.4 - Prob. 29ECh. 14.4 - Prob. 30ECh. 14.4 - Prob. 31ECh. 14.4 - Prob. 32ECh. 14.4 - Prob. 33ECh. 14.4 - Prob. 34ECh. 14.4 - Prob. 35ECh. 14.4 - Prob. 36ECh. 14.4 - Prob. 37ECh. 14.4 - Prob. 38ECh. 14.4 - A college campus plans to provide awnings above...Ch. 14.4 - Prob. 40ECh. 14.4 - Prob. 41ECh. 14.4 - Prob. 42ECh. 14.4 - Prob. 43ECh. 14.4 - Prob. 44ECh. 14.4 - Prob. 45ECh. 14.4 - Prob. 46ECh. 14.4 - Prob. 47ECh. 14.4 - Prob. 48ECh. 14.4 - Prob. 49ECh. 14.4 - Prob. 50ECh. 14.4 - Prob. 51ECh. 14.4 - Make Sense? In Exercises52-55, determine whether...Ch. 14.4 - Prob. 53ECh. 14.4 - Make Sense? In Exercises52-55, determine whether...Ch. 14.4 - Prob. 55ECh. 14.4 - Prob. 56ECh. 14.4 - Prob. 57ECh. 14.4 - Prob. 58ECh. 14 - Explain why the two figures show equivalent...Ch. 14 - In Exercises 2-8, use the following graph.
2....Ch. 14 - Prob. 3RECh. 14 - Prob. 4RECh. 14 - Prob. 5RECh. 14 - Prob. 6RECh. 14 - Prob. 7RECh. 14 - Prob. 8RECh. 14 - Prob. 9RECh. 14 - Prob. 10RECh. 14 - Prob. 11RECh. 14 - Prob. 12RECh. 14 - Prob. 13RECh. 14 - In Exercises 13-15, a graph is given.
a. Determine...Ch. 14 - In Exercises 13-15, a graph is given.
a. Determine...Ch. 14 - Use Fleury’s Algorithm to find an Euler path.Ch. 14 - Prob. 17RECh. 14 - Prob. 18RECh. 14 - Refer to Exercise 11. Use your graph to determine...Ch. 14 - Refer to Exercise 12. a. Use your graph to...Ch. 14 - Prob. 21RECh. 14 - Prob. 22RECh. 14 - Prob. 23RECh. 14 - For each graph in Exercises 24-27
a. Determine if...Ch. 14 - Prob. 25RECh. 14 - Prob. 26RECh. 14 - Prob. 27RECh. 14 - Prob. 28RECh. 14 - Prob. 29RECh. 14 - Prob. 30RECh. 14 - Use the Nearest Neighbor Method to find a Hamilton...Ch. 14 - Prob. 32RECh. 14 - Prob. 33RECh. 14 - Prob. 34RECh. 14 - Prob. 35RECh. 14 - Prob. 36RECh. 14 - Prob. 37RECh. 14 - Prob. 38RECh. 14 - Prob. 39RECh. 14 - Prob. 40RECh. 14 - 41. A fiber-optic cable system is to be installed...Ch. 14 - Prob. 1TCh. 14 - Prob. 2TCh. 14 - Prob. 3TCh. 14 - Prob. 4TCh. 14 - 5. Draw a graph that models the bordering...Ch. 14 - Prob. 6TCh. 14 - Prob. 7TCh. 14 - Prob. 8TCh. 14 - Prob. 9TCh. 14 - Prob. 10TCh. 14 - Prob. 11TCh. 14 - Prob. 12TCh. 14 - Prob. 13TCh. 14 - Prob. 14TCh. 14 - Prob. 15TCh. 14 - Prob. 16TCh. 14 - Prob. 17TCh. 14 - Prob. 18TCh. 14 - Prob. 19TCh. 14 - Prob. 20T
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, subject and related others by exploring similar questions and additional content below.Similar questions
- Throughout, A, B, (An, n≥ 1), and (Bn, n≥ 1) are subsets of 2. 1. Show that AAB (ANB) U (BA) = (AUB) (AB), Α' Δ Β = Α Δ Β, {A₁ U A2} A {B₁ U B2) C (A1 A B₁}U{A2 A B2).arrow_forward16. Show that, if X and Y are independent random variables, such that E|X|< ∞, and B is an arbitrary Borel set, then EXI{Y B} = EX P(YE B).arrow_forwardPls help me with accurate answer plsarrow_forward
- Proposition 1.1 Suppose that X1, X2,... are random variables. The following quantities are random variables: (a) max{X1, X2) and min(X1, X2); (b) sup, Xn and inf, Xn; (c) lim sup∞ X and lim inf∞ Xn- (d) If Xn(w) converges for (almost) every w as n→ ∞, then lim- random variable. → Xn is aarrow_forwardExercise 4.2 Prove that, if A and B are independent, then so are A and B, Ac and B, and A and B.arrow_forwardPls help me asap pls plsarrow_forward
- 8. Show that, if {Xn, n ≥ 1) are independent random variables, then sup X A) < ∞ for some A.arrow_forward8- 6. Show that, for any random variable, X, and a > 0, 8 心 P(xarrow_forward15. This problem extends Problem 20.6. Let X, Y be random variables with finite mean. Show that 00 (P(X ≤ x ≤ Y) - P(X ≤ x ≤ X))dx = E Y — E X.arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
Recommended textbooks for you
- Algebra: Structure And Method, Book 1AlgebraISBN:9780395977224Author:Richard G. Brown, Mary P. Dolciani, Robert H. Sorgenfrey, William L. ColePublisher:McDougal LittellElementary Geometry For College Students, 7eGeometryISBN:9781337614085Author:Alexander, Daniel C.; Koeberlein, Geralyn M.Publisher:Cengage,
- College Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage LearningAlgebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:CengageGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill
Algebra: Structure And Method, Book 1
Algebra
ISBN:9780395977224
Author:Richard G. Brown, Mary P. Dolciani, Robert H. Sorgenfrey, William L. Cole
Publisher:McDougal Littell
Elementary Geometry For College Students, 7e
Geometry
ISBN:9781337614085
Author:Alexander, Daniel C.; Koeberlein, Geralyn M.
Publisher:Cengage,
College Algebra (MindTap Course List)
Algebra
ISBN:9781305652231
Author:R. David Gustafson, Jeff Hughes
Publisher:Cengage Learning
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:9781133382119
Author:Swokowski
Publisher:Cengage
Glencoe Algebra 1, Student Edition, 9780079039897...
Algebra
ISBN:9780079039897
Author:Carter
Publisher:McGraw Hill
What is a Relation? | Don't Memorise; Author: Don't Memorise;https://www.youtube.com/watch?v=hV1_wvsdJCE;License: Standard YouTube License, CC-BY
RELATIONS-DOMAIN, RANGE AND CO-DOMAIN (RELATIONS AND FUNCTIONS CBSE/ ISC MATHS); Author: Neha Agrawal Mathematically Inclined;https://www.youtube.com/watch?v=u4IQh46VoU4;License: Standard YouTube License, CC-BY