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


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

 
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Waterproofness is an absolute requirement as it can run on rainy days!
 

Hello to all of you who are watching MotoMegane. This is kanae.Add to touring with your car X-ADV ... → Continue reading

 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

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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 QP ⇔ Q
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" p と q 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): ï¿¢ ( A ⇔B ) = True
  • q(A, B): (ï¿¢A ) ⇔B = True

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

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