The phrase such that is commonly used in mathematics to designate conditions that a statement is subject to. The handwritten symbol for such that is similar to a right parenthesis with a strikethrough and can be created using MathType thus,
Math textbook often use a symbol similar to a backwards epsilon to represent such that but it is a flipped version of the symbol used to represent set membership. In LateX, a math typesetting language, the names for these symbols are \ni and \in respectively.
People have tried to come up with ways to better represent such that in print. In TeX one can use a macro to combine a \ni with a horizontal line and this is used as a definition. LaTex apparently lacks this capability.
The current usage can potentially lead to confusion. The problem is that one is using a symbol from set theory to represent a control operator. One expression is subject to the control of another. This relationship suggests that the symbol used may be a simplified representation of a trident which was a symbol for power in the religion of ancient Greece. The trident as a symbol is directional and it is clear from context which expression exercises control. A parenthesis with strikethrough would therefore be a better symbol for such that.
Efforts are underway to develop a new version of LaTeX. Perhaps they could include strikeout text within a math statement so that one can create a unique such that symbol. From the computer science perspective it would be better to have a separate "entity," an amperstand-number combination, to designate a sideways trident like symbol for such that.
I should note that both MathType and Wolfram Alpha use a LaTeX \backepsilon or
∍, Extended HTML entity
8717;, for such that. The entity corresponding to \ni or ∋ is
#8715;. (If you see square boxes instead of symbols, try viewing this page in another browser such as Google Chrome or Apple's Safari.)