Update DPLL-Satisfiable.md

Author: ctjoreilly

md/DPLL-Satisfiable.md

@@ -1,4 +1,4 @@
-# DPLL-SATISFIABLE
+# DPLL-SATISFIABLE?
 
 ## AIMA3e
 __function__ DPLL-SATISFIABLE?(_s_) __returns__ _true_ or _false_  
@@ -22,4 +22,4 @@ __function__ DPLL(_clauses_, _symbols_, _model_) __returns__ _true_ or _false_
     DPLL(_clauses_, _rest_, _model_ ∪ {_P_ = _false_})
 
 ---
-__Figure__ ?? The DPLL algorithm for checking satisfiability of a sentence in propositional logic. The ideas behind FIND\-PURE\-SYMBOL and FIND\-UNIT\-CLAUSE are described in the text; each returns a symbol (or null) and the truth value to assign to that symbol. Like TT\-ENTAILS?, DPLL operates over partial models.
+__Figure__ ?? The DPLL algorithm for checking satisfiability of a sentence in propositional logic. The ideas behind FIND\-PURE\-SYMBOL and FIND\-UNIT\-CLAUSE are described in the text; each returns a symbol (or null) and the truth value to assign to that symbol. Like TT\-ENTAILS?, DPLL operates over partial models.