Zetav is a tool for verification of systems specified in RT-Logic language.
Verif is a tool for verification and computation trace analysis of systems described using the Modechart formalism. It can also generate a set of restricted RT-Logic formulae from a Modechart specification which can be used in Zetav.
With default configuration file write the system specification (SP) to the sp-formulas.in file and the checked property (security assertion, SA) to the sa-formulas.in file. Launch zetav-verifier.exe to begin the verification.
With the default configuration example files and outputs are load/stored to archive root directory. But using file-browser you are free to select any needed location. To begin launch run.bat (windows) or run.sh (linux / unix). Select Modechart designer and create Modechart model or load it from file.
The platform’s standout feature is its intuitive invoice and receipt management. Using optical character recognition (OCR), users can photograph a paper receipt or upload a PDF via the mobile app. Lexoffice reads the relevant data (date, amount, tax rate) and creates a digital record. This process seamlessly turns the dreaded "shoebox of receipts" into a tax-ready digital archive. Furthermore, the software generates legally compliant invoices (according to German §14 UStG) with automatic tax calculation, sending reminders for overdue payments via a dunning process.
Lexware Lexoffice: Democratizing Financial Administration for the Modern Freelancer and SME lexware lexoffice
Furthermore, Lexoffice is not an island; it is a hub. It offers robust API integrations with popular tools like DATEV (the standard interface for German tax advisors), payment providers (Stripe, PayPal), and CRM systems. This flexibility allows a business to maintain a "single source of truth" for its finances without changing its entire operational stack. For tax advisors, the ability to access a client’s Lexoffice portfolio directly reduces back-and-forth communication, making tax season more efficient for both parties. The platform’s standout feature is its intuitive invoice
A notable limitation is the absence of robust payroll (Gehaltsabrechnung) within its core plans; users needing payroll must either integrate with Lexware’s dedicated payroll software or use a third-party add-on. Additionally, while the interface is clean, some users find the automation too rigid, occasionally mis-categorizing transactions that require manual override. This process seamlessly turns the dreaded "shoebox of
Despite its strengths, Lexoffice operates in a crowded field. Its primary competitor is sevDesk , which offers similar OCR and bank connectivity but is often cited as having a steeper learning curve. Another major rival is DATEV Unternehmen online , which is more powerful but significantly more complex and accountant-dependent. Compared to international tools like QuickBooks or Xero, Lexoffice is less suited for cross-border VAT handling (e.g., reverse charge procedures for EU services) and lacks native inventory management.
The Zetav verifier expects the input RRTL formulae to be in the following form:
<rrtlformula> : <formula> [ CONNECTIVE <formula> ] ... <formula> : <predicate> | NOT <formula> | <quantifiedvars> <formula> | ( <formula> ) <predicate> : <function> PRED_SYMB <function> <function> : <function> FUNC_SYMB <function> | @( ACTION_TYPE ACTION , term ) | CONSTANT <quantifiedvars> : QUANTIFIER VARIABLE [ QUANTIFIER VARIABLE ] ...Where predicate symbols (PRED_SYMB) could be inequality operators <, =<, =, >=, >, function symbols (FUNC_SYMB) could be basic + and - operators, action type (ACTION_TYPE) could be starting action (^), stop action ($), transition action (%) and external action (#). Quantifier symbols (QUANTIFIER) could be either an universal quantifier (forall, V) or an existential quantifier (exists, E). Connectives (CONNECTIVE) could be conjunction (and, &, /\), disjunction (or, |, \/), or implication (imply, ->). All variables (VARIABLE) must start with a lower case letter and all actions (ACTION) with an upper case letter. Constants (CONSTANT) could be positive or negative number. RRTL formulae in the input file must be separated using semicolon (;).
V t V u (
( @(% TrainApproach, t) + 45 =< @(% Crossing, u) /\
@(% Crossing, u) < @(% TrainApproach, t) + 60
)
->
( @($ Downgate, t) =< @(% Crossing, u) /\
@(% Crossing, u) =< @($ Downgate, t) + 45
)
)
Verif tool does not deal with direct input. Examples are load from files with extension MCH. Those files are in XML and describes model modes structure and transition between modes. There is no need to directly modify those files. But in some cases it is possible to make some small changes manualy or generate Modechart models in another tool.
If you have further questions, do not hesitate to contact authors ( Jan Fiedor and Marek Gach ).
This work is supported by the Czech Science Foundation (projects GD102/09/H042 and P103/10/0306), the Czech Ministry of Education (projects COST OC10009 and MSM 0021630528), the European Commission (project IC0901), and the Brno University of Technology (project FIT-S-10-1).