System and symbolic work
Capabilities, assertions, and diagnostics.
Orientation
The dot system object exposes deliberately granted capabilities. Assertions, symbolic specifications, diagnostics, and tests use that same explicit system boundary.
Prerequisites: Functions and Decisions. For a program-checking route, start with System capabilities and Diagnostics and tests. For symbolic mathematics, start with Assertions and symbolic specs, then Exact symbolic calculus. The advanced notation pages can be read as references when a task needs them.
Compare the dot call with ordinary arithmetic so the capability boundary has a concrete example.
A worked example
The final line is the displayed value; the earlier lines set up the experiment. Keep the setup visible so you can tell whether a name, a cell, or a collection is being reused when the expression changes.
Read the result
The advanced pages show how to ask the runtime for more without making hidden global functions.
Change the two input numbers and verify the result before moving to symbolic or diagnostic work.
Keep going
Continue with System capabilities and then choose a diagnostic or symbolic route.