Recent questions tagged cfl

Let $P=\{a^n\mid n\text{ is prime}\}$.Which statements are correct?$P$ is regular. $P$ is CFL but not regular. If $P$ were CFL, then because it is unary, it would have to...

Let $\text{COPY}=\{ww\mid w\in\{a,b\}^*\}$ and $\text{NOTCOPY}=\{x\in\{a,b\}^*\mid x\text{ is not of the form }ww\}$.Which statements are correct?$\text{COPY}$ is not CFL...

Let $B=\{0^n\#0^{2n}\#0^{3n}\mid n\ge0\}$.Which statements are correct for proving $B$ is not CFL using the pumping lemma?Choose $s=0^p\#0^{2p}\#0^{3p}$, where $p$ is the...

Let $A=\{w\in\{a,b,c\}^*\mid \#a(w)=\#b(w)=\#c(w)\}$ and let $R=a^*b^*c^*$. Which statements are correct?$R$ is regular. If $A$ were CFL, then $A\cap R$ would be CFL. $A\...

Consider the following languages:$L_1=\{w\in\{a,b\}^*\mid \#a(w)=\#b(w)\}$$L_2=\{w\in\{a,b,c\}^*\mid \#a(w)=\#b(w)=\#c(w)\}$$L_3=\{a^m b^n\mid 5m+4n=44,\ m,n\ge0\}$Which ...