Subshifts, the emptiness problem and Lovász local lemma
Subshifts are set of colorings of a group by a finite alphabet that respect local constraints, given by some forbidden patterns ode m. The asymmetric version of Lovász local lemma reveals particularly useful to prove the existence of a coloring inside a subshift, i.e. a coloring that avoids all the forbidden patterns. In this talk I will present some sufficient conditions on the set of forbidden patterns to get at least one coloring. Then we will see as an application why every group possesses a strongly aperiodic subshift (joint work with Sebastián Barbieri and Stéphan Thomassé).
 
     
	
                 
                 
	
                 
	
                 
	
               
	
               
	
               
	
               
	
               
	
               
	
               
	
         
	
           
                       
	
           
	
           
	
           
	
           
	
           
	
           
	
           
	
           
	
           
      
    