HOLTrace
HOLTrace: Verify

The recommended tool for verifying HOLTrace files is holtrace_restore. There are also some experimental tools.

holtrace_restore is a command available in a new HOL Light session after HOLTrace is installed. Running

holtrace_restore !theorems "holtrace-12345.50"

will read and verify a trace file holtrace-12345.50, while checking that the file matches any preexisting name-theorem pairs listed in HOL Light's built-in !theorems database.

On rome1, restoring the pruned 37.5MB trace from hol.ml takes 48 seconds, using about 400MB extra RAM.

Verification remembers named theorems from the file (whether or not those are listed in !theorems), and you can inspect those theorems until they are erased by the next holtrace_restore run:

holtrace_restore_name2thm "ONE_OR_PRIME";;

Verification uses the HOL Light kernel to apply inferences. Verification checks constant definitions in the trace against the kernel's definitions() list, and checks type definitions in the trace against the holtrace_typedef_thms() list (which is maintained by HOLTrace whether or not traces are being saved). For a new definition, verification checks whether the definition can be added to the kernel (so verification is not stateless).

With more work to add bindings for new names and any related syntax, it should be possible to use holtrace_restore as a faster replacement for the normal loading of hol.ml or of other HOL Light libraries. There is also an even faster variant holtrace_restore_skipthmchecks that should be suitable in this context, taking only 24 seconds for hol.ml: this variant skips checking whether the theorem statements match the theorem statements in the trace, but still runs all of the same inferences through HOL Light.

Experimental tools

There are currently two experimental command-line tools for verifying traces. First, holtrace-verify-simple tries to verify traces in essentially the same way that the HOL Light kernel does. Beware that this tool is likely to have soundness bugs that let it accept false theorems: the tool has had vastly less review than the HOL Light kernel.

This tool is written in Python. On rome1, holtrace-verify-simple takes 58.27 seconds and 821MB RAM given the 37.5MB pruned hol.ml trace as input. It takes 6.15 seconds and 125MB RAM given the 2.4MB pruned ONE_OR_PRIME trace as input.

Second, holtrace-verify tries to verify traces and is more efficient than the HOL Light kernel. Beware that this tool is even more likely than holtrace-verify-simple to have soundness bugs that let it accept false theorems: the tool has had vastly less review than the HOL Light kernel and is more complicated than holtrace-verify-simple. Also, this tool currently rejects any substitution producing multiple hypotheses that are different but alpha-equivalent. Furthermore, unlike holtrace-verify-simple, this tool currently does not check whether a name refers to multiple theorems.

holtrace-verify is written in C and is not necessarily safe to run on untrusted input. A VM is recommended.

On rome1, holtrace-verify takes 1.12 seconds and 271MB RAM given the 37.5MB pruned HOLTrace file as input. It takes 0.08 seconds and 20MB RAM given the 2.4MB ONE_OR_PRIME pruned HOLTrace file as input.


Version: This is version 2025.06.16 of the "Verify" web page.