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Apr
19
awarded  abstract-algebra
Mar
26
revised Deterministic finite automata (DFA) (have odd length or end with aaa)
added 346 characters in body
Mar
25
comment Deterministic finite automata (DFA) (have odd length or end with aaa)
No, the initial state is $1$, the other one is a $2$.
Mar
25
comment Deterministic finite automata (DFA) (have odd length or end with aaa)
The empty word neither has odd length nor ends in $\mathtt {aaa}$.
Mar
25
comment Deterministic finite automata (DFA) (have odd length or end with aaa)
Of states $1$ and $4$, only one is an accepting state,so identifying them will lead to an inequivalent automaton. You mean $2$ and $4$, I presume.
Mar
24
answered Deterministic finite automata (DFA) (have odd length or end with aaa)
Mar
24
comment Deterministic finite automata (DFA) (have odd length or end with aaa)
Haven’t checked it. Actually, you probably do need eight states. Have you tried organizing them? Can you tell us what each of the states $1$, …, $8$ describe? (Oh, you have nine states – I think you can toss one.)
Mar
24
comment Deterministic finite automata (DFA) (have odd length or end with aaa)
Did you try finding a smaller automaton?
Mar
14
comment How to prove $(2)=(2x)$ for $x\in \mathbb{Z}$?
No, the statement is not true: For $x = 2$, par exemple, $(2x) = (4) ≠ (2)$.
Mar
6
comment Worst case analysis of MAX-HEAPIFY procedure .
This question is fine here, but it would also be very fine on Computer Science. Just saying.
Mar
4
revised How to prove $\forall x,y\in\mathbb{R}: x^2+y^2 = (x+y)^2 \Leftrightarrow x=0\lor y=0?$
edited tags
Mar
4
comment Identify recursive languages?
This question is okay here, but it would also be very okay at Computer Science. Just saying.
Mar
3
answered Elementary question about the limit $\big( 1 - \frac 1 {\sqrt n}\big )^n$, $n\to\infty$.
Feb
23
comment Fundamental group - space of copies of circle $S_1$
Have you heard of the free product of groups?
Feb
23
comment Kernel of a linear map.
Write out the definition of the kernel and the image, try to find one or two elements for each and ponder which other elements might lie in there.
Feb
23
comment Is there any basis to say the double modulo with the same mod function is the same as the single modulo with the same mod function as before?
You need to define them. Define your stuff and often answers to such questions will come up automatically in doing so.
Feb
22
comment equalisers are unique up to unique homeomorphism
This has little to do with general topology, but with catgeory theory, see for example 640149. Even if you haven’t defined equalizers in that way, look up the categorical definition to have your eyes opened. Or maybe, if you have the time, start with the categorical definition of initial and terminal objects and then work your way up to products, coproducts, equalizers … It’s worth it (or even necessary) in the long run.
Feb
22
comment Why are matrices indexed by row first?
Actually, I am not anymore certain that this is a correct argument. I’ll think about it and get back to this in the unforeseeable future.
Feb
22
revised $\mathbb{Z}$ is a vector space over $\mathbb{Q}$
added 43 characters in body
Feb
21
comment $\mathbb{Z}$ is a vector space over $\mathbb{Q}$
@user1952009 Yes, was this a question?