diff --git a/src/main/kotlin/cz/muni/fi/ctl/Formulas.kt b/src/main/kotlin/cz/muni/fi/ctl/Formulas.kt
index a4a6872..129a9c6 100644
--- a/src/main/kotlin/cz/muni/fi/ctl/Formulas.kt
+++ b/src/main/kotlin/cz/muni/fi/ctl/Formulas.kt
@@ -79,8 +79,8 @@ public fun EG(f: Formula): Formula = FormulaImpl(Op.EXISTS_GLOBAL, f)
 public fun AG(f: Formula): Formula = FormulaImpl(Op.ALL_GLOBAL, f)
 public infix fun Formula.or(f2: Formula): Formula = FormulaImpl(Op.OR, this, f2)
 public infix fun Formula.and(f2: Formula): Formula = FormulaImpl(Op.AND, this, f2)
-public fun Formula.implies(f2: Formula): Formula = FormulaImpl(Op.IMPLICATION, this, f2)
-public fun Formula.equal(f2: Formula): Formula = FormulaImpl(Op.EQUIVALENCE, this, f2)
+public infix fun Formula.implies(f2: Formula): Formula = FormulaImpl(Op.IMPLICATION, this, f2)
+public infix fun Formula.equal(f2: Formula): Formula = FormulaImpl(Op.EQUIVALENCE, this, f2)
 public infix fun Formula.EU(f2: Formula): Formula = FormulaImpl(Op.EXISTS_UNTIL, this, f2)
 public infix fun Formula.AU(f2: Formula): Formula = FormulaImpl(Op.ALL_UNTIL, this, f2)
 
diff --git a/src/main/kotlin/cz/muni/fi/ctl/Parser.kt b/src/main/kotlin/cz/muni/fi/ctl/Parser.kt
index bf90c5e..cf794d6 100644
--- a/src/main/kotlin/cz/muni/fi/ctl/Parser.kt
+++ b/src/main/kotlin/cz/muni/fi/ctl/Parser.kt
@@ -82,7 +82,7 @@ class FileParser {
     }
 
     private fun processString(input: String): FileContext =
-            processStream(ANTLRInputStream(input.toCharArray(), input.length()), "input string")
+            processStream(ANTLRInputStream(input.toCharArray(), input.length), "input string")
 
     private fun processFile(input: File): FileContext =
             input.inputStream().use { processStream(ANTLRInputStream(it), input.absolutePath) }
@@ -135,7 +135,7 @@ class FileContext(val location: String) : CTLBaseListener() {
 
     override fun exitInclude(ctx: CTLParser.IncludeContext) {
         val string = ctx.STRING().text!!
-        includes.add(File(string.substring(1, string.length() - 1)))    //remove quotes
+        includes.add(File(string.substring(1, string.length - 1)))    //remove quotes
     }
 
     override fun exitAssign(ctx: CTLParser.AssignContext) {
diff --git a/src/test/kotlin/cz/muni/fi/ctl/IntegrationTest.kt b/src/test/kotlin/cz/muni/fi/ctl/IntegrationTest.kt
index ca318e1..2d68b7c 100644
--- a/src/test/kotlin/cz/muni/fi/ctl/IntegrationTest.kt
+++ b/src/test/kotlin/cz/muni/fi/ctl/IntegrationTest.kt
@@ -38,7 +38,7 @@ class Integration {
         val pop = True EU (c EU a)
         val f = (EF(True) and EG(pop)) or AX(a)
 
-        assertEquals(4, formulas.size())
+        assertEquals(4, formulas.size)
         assertEquals(a, formulas["a"])
         assertEquals(c, formulas["c"])
         assertEquals(pop, formulas["pop"])
diff --git a/src/test/kotlin/cz/muni/fi/ctl/ParserComplexTest.kt b/src/test/kotlin/cz/muni/fi/ctl/ParserComplexTest.kt
index 45be4c4..37df4f6 100644
--- a/src/test/kotlin/cz/muni/fi/ctl/ParserComplexTest.kt
+++ b/src/test/kotlin/cz/muni/fi/ctl/ParserComplexTest.kt
@@ -43,7 +43,7 @@ class Complex {
         val e = (True and c) or (c and False)
         val d = e implies e
 
-        assertEquals(5, result.size())
+        assertEquals(5, result.size)
         assertEquals(a, result["a"])
         assertEquals(b, result["b"])
         assertEquals(c, result["c"])
@@ -72,7 +72,7 @@ class Complex {
         val d = AG(AX(c))
         val e = (c and True) or (False and b)
 
-        assertEquals(5, result.size())
+        assertEquals(5, result.size)
         assertEquals(a, result["a"])
         assertEquals(b, result["b"])
         assertEquals(c, result["c"])
diff --git a/src/test/kotlin/cz/muni/fi/ctl/ParserIncludeTest.kt b/src/test/kotlin/cz/muni/fi/ctl/ParserIncludeTest.kt
index 2ae66c6..f9e4c61 100644
--- a/src/test/kotlin/cz/muni/fi/ctl/ParserIncludeTest.kt
+++ b/src/test/kotlin/cz/muni/fi/ctl/ParserIncludeTest.kt
@@ -36,7 +36,7 @@ class Includes {
                         "#include \"${ i1.absolutePath }\" "
         )
 
-        assertEquals(2, result.size())
+        assertEquals(2, result.size)
         assertEquals(True, result["val"])
         assertEquals(False, result["val2"])
 
@@ -59,7 +59,7 @@ class Includes {
 
         val result = parser.parse("#include \"${ i2.absolutePath }\"")
 
-        assertEquals(1, result.size())
+        assertEquals(1, result.size)
         assertEquals(True, result["val"])
 
         i1.delete()
@@ -82,7 +82,7 @@ class Includes {
 
         val result = parser.parse(file)
 
-        assertEquals(1, result.size())
+        assertEquals(1, result.size)
         assertEquals(True, result["val"])
 
         file.delete()
@@ -101,7 +101,7 @@ class Includes {
                 "#include \"${ file.absolutePath }\""
         )
 
-        assertEquals(1, result.size())
+        assertEquals(1, result.size)
         assertEquals(True, result["val"])
 
         file.delete()
diff --git a/src/test/kotlin/cz/muni/fi/ctl/ParserReferencesTest.kt b/src/test/kotlin/cz/muni/fi/ctl/ParserReferencesTest.kt
index cc0f71f..73d0156 100644
--- a/src/test/kotlin/cz/muni/fi/ctl/ParserReferencesTest.kt
+++ b/src/test/kotlin/cz/muni/fi/ctl/ParserReferencesTest.kt
@@ -53,7 +53,7 @@ class References {
             m = True
         """)
 
-        assertEquals(2, result.size())
+        assertEquals(2, result.size)
         assertEquals(not(True), result["k"])
         assertEquals(True, result["m"])
 
@@ -105,7 +105,7 @@ class References {
                         "#include \"${ i2.absolutePath }\" \n"
         )
 
-        assertEquals(3, result.size())
+        assertEquals(3, result.size)
         assertEquals(True, result["k"])
         assertEquals(EF(True), result["l"])
         assertEquals(not(EF(True)), result["m"])
@@ -120,7 +120,7 @@ class References {
                 m = !l
         """)
 
-        assertEquals(3, result.size())
+        assertEquals(3, result.size)
         assertEquals(True, result["k"])
         assertEquals(EF(True), result["l"])
         assertEquals(not(EF(True)), result["m"])
@@ -140,7 +140,7 @@ class References {
                         "#include \"${ i.absolutePath }\" \n"
         )
 
-        assertEquals(2, result.size())
+        assertEquals(2, result.size)
         assertEquals(False, result["val"])
         assertEquals(not(False), result["k"])
 
@@ -153,7 +153,7 @@ class References {
             k = True
             l = !k
         """)
-        assertEquals(2, result.size())
+        assertEquals(2, result.size)
         assertEquals(True, result["k"])
         assertEquals(not(True), result["l"])
     }
@@ -163,7 +163,7 @@ class References {
             k = True
             l = k
         """)
-        assertEquals(2, result.size())
+        assertEquals(2, result.size)
         assertEquals(True, result["k"])
         assertEquals(True, result["l"])
     }