RAH Flashcards
An example that proves a statement false is often called a
counterexample
direct approach to proving a conditional of the form “if A then B” starts with the assumption that the antecedent ______________
A is true.
is a false statement
contradiction
starts out by assuming that the statement to be proved is
false
proof by contradiction
another name for proof by contradiction
indirect proof
a smallest number for which a case is false
minimal counterexample
construct an instance of
the object
Constructive approach
where we check that each thing has the stated property.
Exhaustive checking
That if the premise is true, then the conclusion must also be true.
conditional proof
We’ll simply say that a set is a collection of things called its
elements,
members, or objects.
A set with one element is called a
singleton
Sets can have other sets as elements
T or F
T
The set with no elements is called the
empty set or null set
The empty set is denoted by
∅ or {}
is a set or not?
x = {1,2,3,4,5,…}
yes
is a set or not?
x = {1,2,3,…, 35, 37}
yes
equal or not
{u,g,h} = {h,u,g}
equal
equal or not
{h,g, u,h} = {h, g, u}
not
are repeated occurences allowed in sets
no
What are natural numbers?
N={0,1,2,3,4,5,…}
What are integers?
Z = {…,-2,-1,0,1,2,…}
What are rational numbers?
Q={…, -1/2, 0, .08,…}
What are real numbers?
R={…,-2, -1/2, 0, .08, 3, √3, π(22/7),…}
If A ⊆ B and there is some element in B that does not occur in A,
proper subset
A ⊂ B