# 🥾 ｜ [Review] It was the best case to use Montbell's Alpine Cruiser 2000 for bike touring & mountain climbing ### [Review] It was the best case to use Montbell's Alpine Cruiser 2000 for bike touring & mountain climbing

If you write the contents roughly
Waterproofness is an absolute requirement as it can run on rainy days! Moto Megane

Moto Megane is a web magazine that carefully selects and introduces bike gear, motorcycle supplies, motorcycle parts (parts) that are useful for riders, and outdoor equipment that is useful for camping touring.

### Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia. # Equivalent

Equivalent(How) orEquivalent(Toka) is twopropositionTogethertrueOr togetherfalseWill be true whenLogical operation. EnglishThen equivalence (EQ). Abbreviation for "if and only if"iff Also called.Negative exclusive OR (XNOR) be equivalent to. operatorSymbols such as ⇔, ↔, ≡, =, and EQ are used.

## Truth table

proposition Pproposition QPQ
truetruetrue
truefalsefalse
falsetruefalse
falsefalsetrue

## nature

### Basic properties

The basic properties of equivalence are as follows.
( TheLogical conditional(If), TheLogical AND(And))

• Reflection: • Symmetry: • Transitional law: ### More

In addition, it has the following properties.
( Thedenial, TheExclusive OR

• Antisymmetric law: • ## Necessary and sufficient conditions

Two conditions p ,q Against p Everything that meets q When you say, "I also meet." p The q To beSufficient conditionsIs "or" q The p To beRequirementsIs. "

Also," p The q It is a sufficient condition to beq The p "It is a sufficient condition to be", " p The q To beNecessary and sufficient conditionsIs "or" pq AndEquivalentIs. "

### Example 1

A number is XNUMXmultipleIn order to be, that number is at leastevenMust be.That is, being an even number is a necessary condition for being a multiple of XNUMX.However, even if it is an even number, it is not always a multiple of XNUMX.

Also, in order for a number to be a multiple of XNUMX, it is sufficient if the number is a multiple of XNUMX.That is, being a multiple of XNUMX is a sufficient condition for being a multiple of XNUMX.However, even if the number is not a multiple of XNUMX, it is not necessarily a multiple of XNUMX.

On the other hand, in order for a number to be a multiple of XNUMX, the number must be at least an even number.That is, being an even number is a necessary condition for being a multiple of XNUMX.If the number is an even number, the number is always a multiple of XNUMX.That is, being an even number is a sufficient condition for being a multiple of XNUMX.That is, being an even number is a necessary and sufficient condition for being a multiple of XNUMX, and both are equivalent values.

### Example 2

Natural number variable n Conditions for p(n), q(n) Is defined as follows.

• p(n): n > 10
• q(n): 2n > 20

then,p(n) Is q(n) Is a necessary and sufficient condition.That is,n > 10 is 2n It is a necessary and sufficient condition for> 20.

### Example 3

Real variable x Conditions for p(x), q(x) Is defined as follows.

• p(x): x > 0
• q(x): x2 > 0

then,p(x) Is q(x) Is a sufficient condition.But -1 is q(x) Satisfies p(x) Is not satisfied, so "q(x) Are all real numbers p(x) Is not satisfied.Therefore,q(x) Is p(x) Is not a sufficient condition.Therefore,p(x) Is q(x) Is not a necessary and sufficient condition.

### Example 4

Propositional variables with ￢ and ⇔ as logical operations A ,B Conditions for p(A, B), q(A, B) Is defined as follows. (￢ is one mapping from the set {true, false} to the set {true, false}. ⇔ is one mapping from {true, false} × {true, false} to {true, false}. ..A ,B Is the original variable of {true, false}. )

• p(A, B): ￢ ( AB ) = True
• q(A, B): (￢A ) ⇔B = True

then,p(A, B) Is q(A, B) Is a necessary and sufficient condition.That is, "￢ ( AB ) = True "is" (￢￢A ) ⇔B = True ”is a necessary and sufficient condition.