Reputation
302
Top tag
Next privilege 500 Rep.
Access review queues
Badges
1 10
Newest
 Yearling
Impact
~3k people reached

  • 0 posts edited
  • 0 helpful flags
  • 16 votes cast
Jul
6
accepted Find order of elliptic curve
Jul
6
asked Find order of elliptic curve
Jun
26
awarded  Yearling
Jun
26
accepted Factor RSA number $n$.
Jun
26
revised Factor RSA number $n$.
edited body
Jun
26
revised Factor RSA number $n$.
edited body
Jun
26
asked Factor RSA number $n$.
Feb
1
awarded  Talkative
Feb
1
comment How to work with a statement: “for all $x$, if $p(x)$ then $q(x)$” (contradiction and contraposition)
Let us continue this discussion in chat.
Feb
1
comment How to work with a statement: “for all $x$, if $p(x)$ then $q(x)$” (contradiction and contraposition)
The tautologies (K.0)-(K.1) on this sheet might be useful to you: math.ethz.ch/~halorenz/4students/logikGT/Tautologien.pdf
Feb
1
comment How to work with a statement: “for all $x$, if $p(x)$ then $q(x)$” (contradiction and contraposition)
No, $\forall x(p(x) \rightarrow q(x))$ is equivalent to $\forall x:(\lnot p(x) \lor q(x))$ That's right, we leave the outer quantifier be.
Feb
1
comment How to work with a statement: “for all $x$, if $p(x)$ then $q(x)$” (contradiction and contraposition)
Because $p \rightarrow q$ is logically equivalent to $\lnot p \lor q$. Since $\lnot q \rightarrow \lnot p$ is the contraposition of $p \rightarrow q$ your statement is equivalent to $\forall x:(\lnot q(x) \rightarrow \lnot p(x))$
Feb
1
awarded  Teacher
Feb
1
answered How to work with a statement: “for all $x$, if $p(x)$ then $q(x)$” (contradiction and contraposition)
Nov
23
accepted If $\sum_{n \geq 1}X_n$ converges a.s. then $\forall a > 0: \sum P(|X_n|>a) < \infty$
Nov
23
accepted Prove $||A||_2 = max_{x \neq 0, y \neq 0}\{\frac{|\langle y,Ax \rangle|}{||x||\cdot ||y||}\}$ for $A\in \mathbb{K}^{n\times m}$
Nov
23
accepted Prove a random variable has normal distribution
Nov
23
accepted Example: Sum of non-commuting matrices is not normal
Nov
23
accepted Find angle of incomplete rotation matrix
Nov
23
accepted Determine $\frac{\partial}{\partial r} \int\!\!\!\!\!\!-_{B(x,r)} \frac{r}{n} u_{xx}(y)dy$