Need help with Discrete Mathematics definitions

Got an exam on this tomorrow and I've left the revision really late. I've been looking through my notes and the Discrete Mathematics textbook and have found some meanings but I can't seem to find what these mean,

¬
The arrow pointing to the right
The double sided arrows pointing both ways
The Upside down A and E

I'm hoping someone here knows what these means and can help me as I've been trying to find these out for the past hour with no luck. I've seen them used a lot in the textbook but can't seem to find it's definition.

Thanks!!!

Reply 1

Navajo

14

T_Malik

Got an exam on this tomorrow and I've left the revision really late. I've been looking through my notes and the Discrete Mathematics textbook and have found some meanings but I can't seem to find what these mean,

¬
The arrow pointing to the right
The double sided arrows pointing both ways
The Upside down A and E

I'm hoping someone here knows what these means and can help me as I've been trying to find these out for the past hour with no luck. I've seen them used a lot in the textbook but can't seem to find it's definition.

Thanks!!!

Did this in January I think :biggrin:

¬
This means 'not', so if you have ¬A is true, then it means A is false

The arrow pointing to the right
This means 'implies' or 'implication' for example P -> q, this means "if p then q" so if p is true then so is q

The double sided arrows pointing both ways
This <=> means "if and only if", so p <=> q means "p is true if and only if q is true"

The Upside down A and E
Upside down A means "for all", for example "for all x in a"

The E means "there exists" for example "there exists an x in set whatever"

If you want some answers to any questions inparticular then ask me, or add me to your MSN if you want :smile:

Reply 2

Ibrahim

T_Malik

Got an exam on this tomorrow and I've left the revision really late. I've been looking through my notes and the Discrete Mathematics textbook and have found some meanings but I can't seem to find what these mean,

¬
The arrow pointing to the right
The double sided arrows pointing both ways
The Upside down A and E

I'm hoping someone here knows what these means and can help me as I've been trying to find these out for the past hour with no luck. I've seen them used a lot in the textbook but can't seem to find it's definition.

Thanks!!!

¬ means NOT. For example ¬A means NOT A

The arrow pointing to the right means forward implication. For example "A -> B" means A implies B (ie if A is true then so must B be true)

The double sided arrows pointing both ways means both ways Implication. For example A <-> B means "A implies B" AND "B implies A"

The upside down A means "FOR ALL..."
E means "There exist some..."

I hope that helps :smile:

Reply 3

Ibrahim

Navajo

Did this in January I think :biggrin:

¬
This means 'not', so if you have ¬A is true, then it means A is false

The arrow pointing to the right
This means 'implies' or 'implication' for example P -> q, this means "if p then q" so if p is true then so is q

The double sided arrows pointing both ways
This <=> means "if and only if", so p <=> q means "p is true if and only if q is true"

The Upside down A and E
Upside down A means "for all", for example "for all x in a"

The E means "there exists" for example "there exists an x in set whatever"

If you want some answers to any questions inparticular then ask me, or add me to your MSN if you want :smile:

oops didnt see that post... anyways double confirmation for you! good luck

Reply 4

Navajo

14

hehe too slow :biggrin:

Reply 5

Navajo

14

I hated logic maths when I first started but i'm kind of getting to like it a bit.

Mad! I know! :p:

Bit late isn't it for revising for tomorrow such basic fundamentals, but I guess your course is different to mine, or you do as much revision as me :biggrin:

Reply 6

Navajo

14

Oh and good luck tomorrow :smile:

Need help with Discrete Mathematics definitions

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