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location United Kingdom
age 23
visits member for 3 years
seen 16 hours ago

Currently studying for an Msc in Mathematics


Oct
23
answered How can I Prove that $[(p \to\neg q) \wedge q] \to \neg p$ is a tautology?
Oct
23
revised How can I Prove that $[(p \to\neg q) \wedge q] \to \neg p$ is a tautology?
missing or sign
Oct
23
suggested suggested edit on How can I Prove that $[(p \to\neg q) \wedge q] \to \neg p$ is a tautology?
Oct
22
comment Subspace topologies and unions
Ok, cool but it is the union of (union of open balls in A) and (union of open balls in B)- this is what I should have claimed (not the union of an open ball in A and open ball in B). Thanks for the help
Oct
22
comment Subspace topologies and unions
So I just need that any open ball in $A\cup B$ is the union of (unions of open balls in A) and (unions of open balls in B). Then when I'm using the map f I can just consider f on open balls?
Oct
22
comment Subspace topologies and unions
But isn't any open set in B a union of open balls in B as there is a basis of open balls of B?
Oct
22
asked Subspace topologies and unions
Oct
20
revised Probability of rolling 5 dice?
formatting in latex
Oct
20
suggested suggested edit on Probability of rolling 5 dice?
Oct
20
comment showing $\nexists\;\beta\in\mathbb N:\alpha<\beta<\alpha+1$
Sure, just because the op seemed not to want to use subtraction explicitly
Oct
20
comment showing $\nexists\;\beta\in\mathbb N:\alpha<\beta<\alpha+1$
I don't think that will be allowed as subtraction is not defined
Oct
20
comment showing $\nexists\;\beta\in\mathbb N:\alpha<\beta<\alpha+1$
So you have from the definition of addition that $S(\alpha)=\alpha+1$ and so if $\beta > \alpha$ then $\exists \gamma$ s.t. $\alpha+\gamma=\beta$ so then if $\gamma =1$ then$\beta=\alpha+1$ and if $\gamma > 1$ then $\beta > \alpha+1$ which are both contradictions
Oct
20
comment Prove that a formal language is infinite
Argue by contradiction, suppose there was a last word $w_n$ then you could just add an a onto this to get a new word...
Oct
19
revised Probability of not getting kings out of a deck of cards
formatting in latex
Oct
19
revised When is $1^5 + 2^5 + \ldots + n^5$ a square?
formatting in latex
Oct
19
comment Very simple predicate logic deduction question
You can but just to note, you cannot use a constant already in use for $\exists$
Oct
19
suggested suggested edit on Probability of not getting kings out of a deck of cards
Oct
19
suggested suggested edit on When is $1^5 + 2^5 + \ldots + n^5$ a square?
Oct
19
answered Number Theory Problem $ax+by=n$ for $n>ab$
Oct
18
revised How to formulate arbitrary complex trigonometric polynomial?
Formatting latex