remove "safe" (as suggested by Tobias) and added "arith" to "try"
remove "safe" (as suggested by Tobias) and added "arith" to "try"

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle