Expressions use infix notation, with standard operator precedence. Languages that allow arithmetic expressions typically follow the syntax of infix notation with precedence rules. Boundary notation is free of infix, prefix, or postfix operator symbols. The definitions above use infix notation for binary connectives such as formula 14. The wolfram language writes basic arithmetic expressions using infix operators. There are other ways of producing postfix expressions from infix expressions. Another notation is formula 2, an infix notation which is convenient for ASCII. Infix evaluation takes precedence over the prefix evaluation. Locally scoped variables and subroutine names are lowercase with infix underscores. Ordinal numbers are formed with prefix KUMA- (KA- plus infix -UM). The equivalent under infix notation would be "". The infix itself ablauts like root athematic verbs. The subject prefix is placed first, and then the object infix. Arabic uses a common infix, for Form VIII verbs, usually a reflexive of Form I. A further development is the "sweet" "t-expression", which has infix operators without precedence.